Petronella Osgood

Petronella Osgood, PhD was a scientist who worked for UNIT, acting as the scientific advisor to Kate Stewart, in the early 21st century. (AUDIO: The Sacrifice of Jo Grant)

An admirer of the Doctor, she eventually met the Time Lord during the infiltration of UNIT by Zygon invaders, which was resolved by the Eleventh Doctor joined by his tenth and war incarnations. (TV: The Day of the Doctor)

The original Osgood and her Zygon double became indistinguishable from each other to everyone else. They refused to identify which one of them was Zygon and which was human. (TV: The Zygon Invasion) Her Zygon double was later killed by, (TV: Death in Heaven; AUDIO: Narcissus; WC: The Zygon Isolation) but after a Zygon rebellion was ended peacefully, the Zygon rebel leader Bonnie took her place by assuming the form of Osgood to maintain the peace. Both Osgoods still refused to identify whether she was the human or Zygon version, but promised to identify as human or Zygon one day when no one would care anymore. (TV: The Zygon Inversion)

Early life
Petronella Osgood (TV: The Zygon Inversion) was the daughter of Frank Osgood and sister of Nova, (PROSE: For the Girl Who Has Everything) of whom she was jealous. (TV: The Day of the Doctor) She was born into a family of science geeks, (AUDIO: Earthfall) which included an aunt whose house had a number of makeshift electrical connections, (AUDIO: Time of the Vulpreen) and had family connections with UNIT. (AUDIO: Power Cell)

When Osgood was young, she was part of a chess club. (AUDIO: Vanguard) She went on to study at King Henry's University in London, where she befriended Jay Roy, (AUDIO: Power Cell) and achieved at least one PhD. (AUDIO: The Sacrifice of Jo Grant) Following university, she was employed by the Ministry of Defence at Dstl where she was mentored by Professor John Torrance. (AUDIO: The Sontaran Project)

Joining UNIT
Osgood was recruited into UNIT in November 2011, (PROSE: For the Girl Who Has Everything) having been given a favourable reference by John Torrance. (AUDIO: The Sontaran Project) She had a familial relationship with somebody in UNIT whom she assumed John Benton would have met. (AUDIO: Call to Arms) Indeed, Benton worked alongside technical officer Tom Osgood. (TV: The Dæmons, etc.) During basic training, she was ejected from a submarine and was sick in her helmet. (AUDIO: Tidal Wave)

Much to Kate Stewart's delight, the pieces of technology that Osgood created to aid in UNIT's missions were typically to stop the soldiers from shooting at aliens. (AUDIO: Vanguard) She became very familiar with Sontaran biology and had the opportunity to examine one or two of them. (AUDIO: The Sontaran Project)

Although Osgood did have free time, she spent most of it at work and made a hobby of looking through artefacts such as those recovered from the Silurians. (AUDIO: Retrieval) She hardly saw anybody outside of her job and did not have time to contemplate romance, although several people assumed that she was with Josh Carter, who sometimes flirted with her. (AUDIO: United)

Osgood enjoyed reading files on the Doctor's exploits (AUDIO: Call to Arms, Tidal Wave) and took to dressing like several of their incarnations, namely the Third, (AUDIO: Tidal Wave) Fourth, (TV: The Day of the Doctor) Sixth (AUDIO: Earthfall) and Eleventh Doctors. (AUDIO: Power Cell) She and/or her Zygon duplicates would later dress like the Seventh Doctor as well. (TV: The Zygon Invasion) She idealised several of the Doctor's companions (AUDIO: Call to Arms, Tidal Wave) and, at some point, met Sarah Jane Smith. (PROSE: The Day of the Doctor)

Preventing a Nestene invasion
Osgood tracked a set of energy units falling to Earth and warned Vikram Shindi about it. (AUDIO: Vanguard) Together with Lieutenant Sam Bishop, she was deployed to the Gobi Desert in Mongolia in search of a Nestene energy unit. She had created a holographic image projector from alien technology. (AUDIO: Earthfall)

She tried to examine the energy unit using all the techniques she could think of. Kate also told her to examine one of the 3D printers. When the Nestene escaped the energy unit, she discovered that the Nestene could combine through the internet. (AUDIO: Bridgehead)

She created a new weapon to destroy the Autons and was able to free Captain Josh Carter from Nestene control. (AUDIO: Armageddon)

Tengobushi incident
After going to a pub quiz with Jay Roy, she was tasked with working out which pieces of UNIT property Lyme Industries had managed to get their hands on. She later asked Jay to help her in her work in order to work out what was kidnapping people. She started to show Jay the ropes but didn't get too far when a Tengobushi attacked. Jay decided to protect her and detonated a bomb in her flat killing himself in the process. (AUDIO: Power Cell)

Osgood went to Geneva and decided to visit local Galleries, where she was followed and attacked by Dokan. She later went with Kate and Grant Avary to investigate a set of murders on a French mountainside. She returned to Geneva to analyse some secretions and was attacked by the Tengobushi but was save by Josh. She realised that the Tengobushi wanted her for her knowledge of an alien artefact and used this to get into their ship. (AUDIO: Death in Geneva)

Osgood and Kate had to fly their plane after the Tengobushi killed the pilots during their flight. She then investigated the Kamishi energy cell in the surroundings of the Black Archive. As part of her experiments, she accidentally released some power that caused some earth tremors. After the Tengobushi released an energy barrier around the Tower of London, she released the ravens to observe their advance. During the attack, Osgood was trapped in the Archive until Josh helped get her first to the Jewellery room and then to command centre. She managed to work out how to use the energy cell and weaponised it to aid their escape. (AUDIO: The Battle of the Tower)

When they were under lock and key in UNIT's base under the Rock of Gibraltar, Osgood managed to hack into the base's computer to get their release. Whilst at Lyme's base in Antarctica she worked out a way to destroy the generator and destroyed it with the help of Dokan, who questioned her about her actions. (AUDIO: Ice Station Alpha)

Investigating the Silence
Osgood received a panicked call from Colonel Shindi who detected something near Helena Faversham's residence. While she was tracking the Silents, she kept forgetting the positive readings, and after she was attacked by the Silents, she soon forgot. She then questioned Faversham using a truth serum. (AUDIO: House of Silents)

Osgood worked on a universal translator which could understand Axons and Sontarans. She helped Bishop investigate what happened at the Faversham estate and later worked out a simplistic way of remembering the Silents: by writing stuff down. Investigating the people that went to Faversham's home, she started with the ones closest to her but they all disappeared. She and Bishop tracked Derek Butler but he was snatched from under her nose. She then looked through all the videos the people she was looking for had made and found subliminal messages to get the UK population to trust Kenneth LeBlanc. (AUDIO: Square One)

A month later, she had to brief the rest of UNIT about her solution to getting the rest to remember the Silents. She had created a pair of sunglasses which had 360-degree cameras which could give them all views of the Silents. She called the Silents "Edvard". After she stole Carter's laptop, using the same techniques the Silents used, she found a large order of guns and explosives he had ordered. She discovered from Heston where he had taken the things Josh ordered. She then tried to convince Josh not to kill LeBlanc but couldn't, so she knocked him out. (AUDIO: Silent Majority)

Osgood went with Bishop to the UNIT satellite to fix something there, but they were knocked unconscious upon arrival. Later, she started to explore the space station and found a Silent on-board. She discovered that the crew were being controlled by the Silents and had exposed the spy satellites of all the governments of the world. She tried to get the Telokni ship to stop shooting them, but couldn't and had to escape. (AUDIO: In Memory Alone)

Jastrok's revolution
Per the Earth Reptile Initiative, Osgood and Kate checked on a Silurian nest at Scafell and were attacked by Jastrok and his warriors, whom Captain Burmaster was able to keep back long enough for the two of them to escape to John Benton and Mike Yates at the White Hart. Osgood managed to contact Josh for reinforcements and, realising that the Silurians were vulnerable to sudden changes in temperature, set the beer in the cellar alight and created a backdraft. The group escaped in Bessie and the nest was destroyed, apparently by Burmaster. (AUDIO: Call to Arms)

When Kate sent Osgood to observe Project Charybdis with Jo Jones, Osgood put on a velvet jacket like the Third Doctor's and kept asking Jo to tell stories. They were locked away by Burmaster, who was under Jastrok's control, but they managed to escape and were recovered by Kate. To prevent UNIT and the Sea Devils from killing one another, Osgood sent Jo in a submersible to speak with Krelix and persuade him and his people to return to hibernation, a plan which proved to be successful. She and Kate then went to deal with Krelix's escaped hybrids. (AUDIO: Tidal Wave)

Searching for a device to control the hybrids, Osgood identified a Silurian nest in Greece as a research base and headed there with Kate, soon to be joined by Sam. Tryska used a fear trigger on Osgood to amplify her race memory, making her terrified of the Silurians and making her flee into the caves where Sam saved her. Although they were unable to find any useful technology before the base was destroyed and they were airlifted to safety by Josh, Kate did manage to upload Silurian data to the UNIT Cloud. (AUDIO: Retrieval)

Osgood and Josh had to take a mini-submersible to get close enough to Great Britain to transmat there due to pterosaurs and Krelix's hybrids besieging the island. She worked on adapting a psion cannon to release the creatures from the Silurians' control and Jo took it with her to confront Jastrok at the Houses of Parliament. Osgood, Yates, Benton and Josh went to save Jo from Kalana, who had started a nuclear countdown which Osgood managed to stop, and the creatures were released from Silurian control thanks to the device. With the threat ended, Osgood went with Jo and Sam to South America to relocate the sea creatures. (AUDIO: United)

Investigating the Auctioneers
Undercover as cyber-terrorist "Tara Winters", Osgood joined Kate, Josh and Shindi in flying to Monte Bosque to investigate what turned out to be a Dalek tracked by Sam, who had gone missing whilst looking into the Auctioneers. Their cover was blown and Osgood and Josh were locked up whilst the Dalek escaped and killed several of Maria Gonsalves's guerillas before apparently being killed in a tank. Osgood realised that it had deceived them by shedding some of its limbs and they tracked it down and defeated it. She wanted to take the Dalek mutant to try to understand it, but the Dalek self-destructed and the group were rescued by UNIT North America. (AUDIO: The Dalek Transaction)

On Hallowe'en, Osgood stayed late at work and picked up a transmission from an obsolete Voxtel satellite, part of which was in Latin. She and Josh, who told her about his experience with the Grey Man, flew to Ealdon House after Kate failed to check in with them. There, Osgood discovered that the Grey Man apparititions were caused by infrared sound sent by aliens who picked up the transmissions sent by the satellite in the 1960s. She was able to get access to the satellite and, following Kate's order, sent a message which put an end to the phenomena. (AUDIO: Invocation)

Osgood attended the New Science Conference as UNIT's delegate and ran into John Torrance, who took her to the Torrance Research Foundation and showed her his Sontaran clones. She tried to leave but was sedated by Torrance and Christine Colley using a truth serum which, thanks to Malcolm Taylor, she was immune to. By pretending to be unconscious, she overheard them talking about the Overseer. She met Merx, whose experience she sympathised with, and was rescued by the allied forces of UNIT and Marshal Skar. With the cloning project and the Foundation shut down, Osgood took Max, a monkey clone, to safety. (AUDIO: The Sontaran Project)

Osgood and Josh were accidentally transported to a parallel universe by a transport capsule recovered from the Auctioneers and were left stranded when the capsule malfunctioned. Osgood went to collect power cables and ended up encountering that world's Osgood and Josh, who were in a sexual relationship. When Josh and her other self used the capsule, Osgood followed through the dimensional tear and later helped her other self leave, although she could not tell whether or not she would survive the trip. (AUDIO: False Negative)

After receiving a recording from Sam, Kate and Osgood went to save him and were given various tasks by the Overseer involving virtual reality. These tasks led Osgood to defuse a Krillitane detonator and fly a virtual jet to Heathrow Airport to switch off an emitter. Upon completing the tasks, the Overseer allowed the two of them to speak to Shindi, who told them that a container that Malcolm could detect no signals from had appeared at Windsor Castle. Osgood opened it and found Sam inside. (AUDIO: Game Theory)

On examining the VR equipment, Osgood realised it was a bridge to another universe. She, Carter and Shindi experimented in the virtual world. She thought that it was amazing that they could actually interact with the parallel world. In this world, they were attacked by mutated dogs and then by metal worms. Osgood observed that the dogs had been converted and realised that the world could be affected by their imagination. She became concerned when they realised they were on a parallel Earth. She thought that there was something familiar about the hive she saw in the virtual world. She started to be cyber-converted. (AUDIO: Telepresence)

Osgood was connected to the cyber-network. She stopped the Cybermen from fully converting Bishop and Shindi. She told the Cybermen that the reason she wasn't fully converted was because they were using emotional responses. She tried to work out what they were doing and told them that she could get the whole Earth under control within a matter on minutes. She planned to use the Auctioneer app to use this. She got the Cybermen to find Kate in order for her to reverse the communications blackout. Using her improved hacking skills, she undid Kate's communications shield and sent the app to everyone on Earth. (AUDIO: Code Silver)

Osgood realised that was in the UNIT base and updated the Cybermen on him as well as getting her gun that might stop him. She asked the Cybermen to convert the Master. She sent Shindi and Bishop after Kate, the Master and Carter. She again had to remind the Cybermen not to convert her, and showed them her usefulness by changing a conversion unit to work on a Time Lord. She placed the Master in the conversion chamber. Shortly afterwards she was uncoverted. She was used by the Master as a hostage so that he could escape. Later, she rewrote the app again to uncovert the humans. (AUDIO: Master of Worlds)

Alien incursions
Kate told Osgood to deliver what the Master had found in the Auctioneer's vault to the Well. She later interviewed Shana Siddiqui for a position. During her time in a decontamination suit, she wore a stick of celery. She asked Shana to help her study a Wirrn. After the Wirrn escaped, she discovered that Shana had been infected and planned to study the infection. She tried to get Shana to resist the infection. She used the Ravens to attack the Wirrn. After discovering that it was an ancient virus that killed the Wirrn, she injected Shana with one from the Archive. (AUDIO: Hosts of the Wirrn)

Whilst undertaking an experiment, Osgood was interrupted firstly by Josh and then by a capsule coming to the Tower. She worked on trying to translate the language of the creatures. She later explored the Black Archive for a weapon Vara had told her about. She wasn't happy that Kate was going to hand over the aliens to her people, and thought it wasn't fair. She supplied Vara with the weapon. (AUDIO: Breach of Trust)

She joined Kate on an investigation to the Pandora Institute. Whilst there, she experienced a nightmare where she was useless to stop an invasion. She managed to get back her communications device and contacted Shindi. She later told Josh of this, and they realised that they had both heard the same noise. She worked out that Seth Hyer projected the fears of the patients which made some of them die. She got Shindi to send a platoon to the island as there was an alien incursion. She then reconfigured her holograms to reflect Seth's own image which destroyed it. (AUDIO: Open the Box)

Kate took Osgood and Josh to Abbey Marston in order to resurrect Warren Calder and find out where he hid the Silurian plague that he claimed to have stolen shortly before ending his own life. This was revealed to be a ruse by Calder who wanted Kate to resurrect him in Abbey Marston so that he could use the stone circle to steal a new body and cheat a terminal illness that he had been diagnosed with. However, in doing this, he released the Static, who planned on stealing bodies of their own so that they could exist on Earth. They were defeated by Kate, Osgood, Josh and Calder when they destroyed the stone circle. (AUDIO: This Sleep of Death)

Osgood and Sam Bishop investigated unusual weather conditions revealed to have been caused by the Animoi. (AUDIO: Tempest)

Osgood investigated her own murder when her body was discovered within a power station. She was suspicious of the director, known as "River Song". However the director was in fact a Wampeerix Battle Queen masquerading as River Song, intent on feeding off the energy of the Earth. The real River Song aided Kate and Osgood in defeating the Wampeerix. (AUDIO: The Power of River Song)

Meeting the Doctor
Osgood was present when the TARDIS, with the Eleventh Doctor and Clara Oswald inside, were brought to the National Gallery in an effort to understand what had happened to several paintings in the Under Gallery. The Doctor took a liking to her long multi-coloured scarf, which was strikingly similar to one he wore in his fourth incarnation. She displayed a type of hero-worship belief in the Doctor, twice "praying" to him to save her during moments of danger.

On the Doctor's orders, she and fellow scientist McGillop analysed the stone dust in the Under Gallery and eventually realised that the dust on the floor was the remains of the statues, which had been smashed by Zygons that had escaped from the paintings in order to hide. She was cornered by a Zygon, who took her form. The Zygon disliked the fact that Osgood was asthmatic, and, annoyed at "getting one with a defect", promptly took her inhaler. Osgood escaped by tripping the Zygon with her scarf, and reclaimed her inhaler.

She made her way to the Black Archive, and was present along side her Zygon-double when Kate threatened to destroy London, rather than let the alien technology in the archive fall into Zygon hands. Like the other humans and Zygons in the room, her memory was temporarily cleared by three incarnations of the Doctor, so that she could not recall whether she was the real Osgood or her Zygon duplicate. As peace talks ensued, she realised who the real Osgood was when the Zygon duplicate began wheezing and did not have the inhaler. She gave it to the Zygon, and both Osgoods agreed to keep their discovery a secret so as not to disrupt the peace talks. (TV: The Day of the Doctor)

Operation Double
The two Osgoods created Operation Double, where a group of 20 million Zygons would be allowed to live on Earth and take on the form of the nearest person they could find. The treaty could only be maintained if both humans and Zygons agreed to live among each other in peace, and that no harm would come to anyone. They were given a device called the Osgood Box by the Doctor, only to be used only in a dire emergency. (TV: The Zygon Invasion)

In 2014, one of the Osgoods was sent to Bonnybridge to investigate another U.F.O. sighting in the area. Because of this, she missed the first known interaction between the Twelfth Doctor and UNIT as well as the Fractures' attack on London. (COMIC: The Fractures)

After her Zygon double was killed by, (TV: Death in Heaven; AUDIO: Narcissus; WC: The Zygon Isolation) Osgood refused to state whether she was the Zygon or the human in order to maintain the treaty. She became a target of a revolt from a rogue group of Zygons who believed they had been betrayed. (TV: The Zygon Invasion)

After the Doctor convinced Bonnie, the leader of the Zygon revolt, to stop her plan, Bonnie also assumed Osgood's form and acted as the second protector of Earth alongside the other surviving Osgood. She felt that they were a credit to both humans and Zygons and planned to take on the role of protecting the Earth from threats. (TV: The Zygon Inversion)

The Osgoods created a series of files documenting alien species and foes encountered by the Twelfth Doctor beginning with the Zygons and their involvement in Truth or Consequences. Other files documented King Hydroflax, the Mire, The Veil and the Sandmen. (PROSE: The Osgood Files)

In September 2015, the two Osgoods watched prime minister Daniel Claremont's speech on global warming at Ravenscaur School with Kate Stewart in the Tower of London. After Claremont was revealed to be a Sea Devil during the speech, the Osgoods recommended that Kate call the Doctor. The Twelfth Doctor was already there and he defeated the Sea Devils without UNIT. (COMIC: Clara Oswald and the School of Death)

In early 2016, one of the Osgoods was in London when it was attacked by K2. She called the Twelfth Doctor and he took her into his TARDIS. They materialised above the London Eye as it was attacked by the robot. The Doctor used his sonic screwdriver to destroy K2, but he fell out of the TARDIS. Osgood saved him by throwing her scarf out of the TARDIS for the Doctor to catch. (COMIC: Robo Rampage)

On the eighth of March of an undisclosed year, Bonnie and Petronella struggled to work together at the UNIT lab until they discovered that Josh Carter had mysteriously disappeared the night before.

Together, they decided to investigate the Narcissus dating website and find Josh. Bonnie took the form of Jacqui McGee using her Narcissus profile and met with Jordan Love, who appeared as someone she knew during her reproductive days. However, Jordan soon discovered that she was an imposter and attacked her with a burst of energy that would’ve killed a human, but being a Zygon, she was able to survive albeit injured.

Meanwhile, Petronella prepared to confront Jordan Love on their spaceship. Bonnie tried to stop her, believing that she was more disposable than her sister. Petronella went ahead with the mission anyway and unwittingly defeated Jordan due to her complete self-reliance and contentment being toxic to them. Josh was rescued and returned to UNIT. Following these events, Bonnie and Petronella reconciled, agreeing that two Osgoods are better than one. (AUDIO: Narcissus)

Protecting the Arch
One of the Osgoods analysed the Arch after it was found by Adam Merchant's team and, when he disappeared through it, she correctly determined that he had been teleported and helped Kate and Josh search for him when he returned. When the Eleven took Kate hostage, Osgood and Josh used the Lionheart Protocol to lure him onto a UNIT plane, but he managed to escape. Osgood tried to analyse the antitoxin that the Eleven gave to the infected Merchant and believed that she needed the help of Harry Sullivan. (AUDIO: The Enemy Beyond)

Osgood and Kate flew to the Northern Territory to meet up with Harry and Naomi Cross. They tracked them down using Ros Green's social media and were forced to land by Jakernia, who later invited them, as well as Harry and Naomi, aboard her spacecraft. Harry was able to replicate the antitoxin using Ice Warrior data and the group were returned to the United Kingdom, with Osgood being worried about what the Eleven might have been up to whilst they were away. (AUDIO: Fire and Ice)

On Middle Mouse, Osgood found a way to disable the Arch using a device adapted from the Sontarans' teleport technology and assisted Kate and Josh in trying to thwart the Eleven using a hologram projector. She was later joined by Jacqui, followed by the Eleven and Ava Drake and her gang. Due to Osgood having temporarily deactivated the Arch through complex matter realignment, the Eleven was unable to make use of it and fled. (AUDIO: Eleven's Eleven)

With the Arch hidden in the Under Gallery with the Curator, whom she found familiar, Osgood set a trap for the Eleven in the National Gallery's lift which ultimately failed. The Curator took her, Kate and Josh into the J. M. W. Turner painting in which the Arch was hidden and Osgood prepared to destroy it with a disruptor to keep it from falling into the Eleven's hands, but Jacqui fell through it and the Eleven was captured. (AUDIO: The Curator's Gambit)

Vulpreen and the Void World
Osgood worked for three months to better understand the Arch in the hopes of realigning it and bringing Jacqui back. She and Jimmy Tan were accidentally teleported aboard Hasper's Battle TARDIS when he came for the Eleven and the Arch and learnt about the Vulpreen. Jacqui returned through the Arch with Orgus, whom Kate had to shoot and kill to save Osgood and Jimmy, and the Arch was later stolen by the Eleven. (AUDIO: The Man From Gallifrey)

After Naomi recognised Director Prast as a Dominator, Osgood and her attempted to surveil Portstone New Town with a Cyberman omniscope whilst Kate and Harry went undercover. They met Junaid Mirza and used a glider to enter the supposed town which they found was a slave camp. Osgood reprogramed a Quark, whom she named Quentin and whom she and Naomi missed after the Dominators were defeated and Quentin returned to his storage pods with the other Quarks. (AUDIO: Power of the Dominators)

Jacqui pulled Osgood through a time fracture when temporal anomalies appeared around the Arch at Royal Arsenal and they arrived in a future where humans and the Vulpreen were at war. Osgood realised that Jacqui had been brainwashed during her imprisonment on the Void World and tricked her into taking a message for Kate when she left her to be killed by Sorka. Osgood was saved by Private Jane Huff and returned to her own time where she sealed the fracture with a temporal modulator. (AUDIO: The War Factory)

Osgood was appalled with Josh for ordered a bombstrike to destroy the Arch after it opened given that Kate had been taken inside by a Vulpreen Commander. The two of them managed to get past the Vulpreen and the Eleven and passed through the Arch where they were reunited with Kate and returned to Earth. The bombstrike hit the Arch shortly afterwards, inadvertently giving it the power to free the Vulpreen. (AUDIO: Ten Minutes in Hell)

The Vulpreen invasion
Accompanied by Jimmy and several other UNIT soldiers, Osgood boarded the UK Space Agency's Starseeker to investigate an unusual asteroid which they found to be a Vulpreen spacecraft. The Starseeker was destroyed after Osgood and the UNIT soldiers landed on the craft in a shuttle; there, Osgood and Jimmy were taken prisoner by Commander Krillen and subjected to psychic attacks to prepare them for interrogation. Osgood managed to free herself and Jimmy from their cell and they returned to Earth through an arch, followed by Vulpreen. (AUDIO: The Vulpreen Encounter)

Osgood created an air tunnel to allow her, Kate and Jimmy to escape underwater whilst Jacqui distracted the Vulpreen and was captured. After being rescued by Naomi, Osgood went with her to inspect a new arch at Alberta and found Yang Li freezing in the snow, giving her a survival suit to warm up. She saved Naomi with a chrono-gauge when she was trapped by a temporal snare and watched as the Axons began to emerge from the arch. (AUDIO: By Jacqui McGee)

With Kate and Jimmy having disappeared, Osgood and Li went to Norway to investigate Josh's report of rapidly-growing trees, which she found was due to Axonite contamination. She realised that Axos could not absorb hydrogen and had UNIT release liquid hydrogen near the arches when it began its feeding process, during which she travelled through the arch to save Kate from Axos using bleach. Osgood attended Kate's small memorial for Jacqui and, afterwards, watched Lord Varliss's message as the Vulpreen invasion of Earth began. (AUDIO: Axos Unleashed)

Osgood oversaw the missions to surround the hundreds of arches and planned to spread the effects of the Eleven's time field inhibitor to leave the arches vulnerable using the Internet. She said goodbye to Josh using the holographic projector and helped the Eleven repair the inhibitor after it was damaged, but it failed. She was reunited with Josh and helped Kate escape by helicopter from Varliss, from whom Osgood learnt that the Vulpreen were being assisted by. (AUDIO: Time of the Vulpreen)

Continued career
One of the Osgoods was picked up from UNIT HQ by the Twelfth Doctor while the other had gone out to pick up some coffee. The Doctor took this Osgood on her first trip in the TARDIS and asked her to prepare a briefing for him after they arrived on Nayspiel, the capitol mega-city of the Alliance. They stopped a plot by the Lisban corporation to invade the planet Albensi. The Doctor returned Osgood to UNIT HQ just in time to see the return of her sister. (AUDIO: Field Trip)

In October 2016, one Osgood mailed the other based on a large increase of transmitter activity coming from Saxon Heights. They realised that this was Missy and later had UNIT crash into the school. However Osgood later confirmed to Kate Stewart that they had lost her. (PROSE: Yes, Missy)

One of the Osgoods was the commanding force behind UNIT's shutting down of Harmony Shoal Institute, following an anonymous tip off. (TV: The Return of Doctor Mysterio)

The Doctor invited her on a trip in the TARDIS to a planet who were in the midst of planning an invasion. Osgood witnessed the debate and had some suggestions to improve policy. A couple of people tried to stop the proceedings and the Doctor asked her to chase after one of them. She was eventually caught and interrogated by one of them and discovered that the assailant was trying to stop the invasion. Osgood was then placed undercover to help the Doctor plant a virus in a private company's servers. She used one of her gizmos to jam the signals to help the Doctor talk to the invaders. (AUDIO: Field Trip)

When Jenny's bowship crashed into the Terrance Dicks Library, one of the Osgoods examined the craft only to wind up infected with the white energy from the Void. Spreading the infection to the other UNIT troops, she was slaved to the will of a rogue Type 1 TARDIS before the Doctor managed to have the Type 1 stand out. (COMIC: The Lost Dimension)

2020s
Following a failed assassination attempt on Kate Stewart by the Grand Serpent, Kate called Osgood and told her she was going dark. (TV: Survivors of The Flux)

On 10 May, 2020, at around 18:30 pm, Osgood and her Zygon duplicate watched The Zygon Invasion, an episode from the ninth series of Doctor Who. (WC: The Zygon Isolation)

In 2022 Kate disappeared (AUDIO: Recruits) due to the psychic virus that had infected the Thirteenth Doctor and was erasing people who'd had contact with her, (AUDIO: Salvation) so Osgood took over as Chief Scientific Officer of UNIT. She spoke to the hosts of The Blue Box Files at the Black Archive in the hopes of them helping with UNIT's fading records of the Doctor, taking a particular interest in Abby McPhail who she offered a place at UNIT. (AUDIO: Recruits)

As more and more of the population disappeared, Osgood led experiments on one of the ghosts that had started appearing, insisting they had to carry on despite Abby's concerns about the tests. (AUDIO: Requiem) Osgood subsequently disappeared herself, (AUDIO: Rescue) however the Doctor and Cleo Proctor later restored all the disappeared. (AUDIO: Salvation)

Personality
Osgood was a "fan" of the Doctor and knew of many of his previous incarnations. She would pick iconic items (i.e. multi-coloured scarf, bow tie) from the incarnations she knew of and wore them herself. (TV: The Zygon Inversion) When asked by the Twelfth Doctor if she would like to travel with him, she was so excited that she had to use her inhaler. (TV: Death in Heaven) Osgood would become saddened if she learned she missed a chance to see the Doctor; one of her fellow scientists even stated she would be disheartened to learn the Doctor had regenerated again after she had just started mimicking his previous self's fashion. (COMIC: The Fractures)

Osgood was very intelligent. She alone was able to work out the reason why the Zygons smashed the statues in the Under Gallery. (TV: The Day of the Doctor) She also surprised the Twelfth Doctor by correctly presuming that Missy was the Master regenerated into female form: UNIT kept files on all past Prime Ministers, including the Master. (TV: Death in Heaven) She also came up with a hypothetical plan for invading Earth by killing the Doctor by shooting him between the eyes for each regeneration, never allowing him to talk. (TV: The Zygon Inversion)

She managed to figure out whether she or her Zygon doppelganger was the real Osgood after the Tenth and Eleventh Doctors, joined by the War Doctor, jumbled their minds, making them unable to determine their own species, in an attempt to facilitate negotiation of the ultimate peace treaty. She discovered this when her Zygon counterpart suffered an asthma attack, motivating her to pass her asthma inhaler to the other Osgood. (TV: The Day of the Doctor)

Osgood had a sister to whom she negatively compared herself. Missy observed that she had little confidence in herself. (TV: Death in Heaven) Osgood proved capable of such courage, and was willing to fight back and go to the rescue. (TV: The Day of the Doctor, The Zygon Invasion|The Zygon Inversion)

Appearance
Osgood dressed according to the Doctor's fashion senses from various incarnations, choosing to wear a similar scarf to that worn by the Fourth Doctor. (TV: The Day of the Doctor, COMIC: Robo Rampage) She also wore an olive green moleskin overcoat and a burgundy bow-tie similar to those worn by the Eleventh Doctor. (AUDIO: Tidal Wave) She also wore a shirt with question marks on the collars, like the Fourth, Fifth and Sixth Doctors. When the Nightmare scenario occurred she wore items of clothing similar to the Seventh Doctor when he visited Maiden's Point. (TV: The Zygon Invasion) On at least one occasion she wore a costume inspired by the Sixth Doctor. (COMIC: The Lost Dimension) When Kate sent Osgood on a mission with Jo Jones, she wore a velvet jacket and a frilly shirt like the Third Doctor. (AUDIO: Tidal Wave)

She had tattoos of the Doctor's various incarnations across her body, and wanted to add all of their faces eventually. (PROSE: The Day of the Doctor)

A parallel Osgood was surprised at how mousy her other self looked. (AUDIO: False Negative)

Behind the scenes

 * On 24 July 2014, Ingrid Oliver appeared in-character as Osgood in a video thanking fans for helping the official Doctor Who Twitter account reach one million followers.
 * Osgood appears as a background character in the London scene and the hidden Black Archives location in the Doctor Who level pack in LEGO Dimensions.

Family ties

 * In DWM 484, Steven Moffat admitted his intention when writing was for Osgood to be the daughter of UNIT soldier Tom Osgood from the Third Doctor era. However, he did not want to state this definitively in the script so fans would be able to form their own interpretations.
 * In the audio story Power Cell, Osgood responds to the suggestion that she had an uncle who used to run around shooting aliens with "something like that". This is consistent with the theory that Tom Osgood is Osgood's father and with the lack of definitive confirmation.
 * In the audio story Call to Arms, John Benton says Osgood is "just like him", and she automatically assumes he means someone specific other than the Doctor — "you mean, just like my..." — but her inquiry cut short before she names them.
 * In the short story For the Girl Who Has Everything, however, Osgood's father is named Frank, though this confirmation does not negate the possibility of Tom Osgood still being related to Petronella.