The Good Companion (comic story)

 was the fifth and final story (sixth counting COMIC: The Lost Dimension: The Tenth Doctor) of the third year of Doctor Who: The Tenth Doctor, published in 2017 and 2018.

The story ends on a cliffhanger that is partially followed up on in Catch a Falling Star. Otherwise, it is, to date, the last chronological story to depict the Doctor's travels with Gabby and Cindy, leaving their travels together unresolved.

Part 1
In New York City, Cleopatra Hunsicker is running through an alleyway, avoiding being shot by a man. Cleo sneaks up behind him and puts a gun to his head. She takes a device from him, telling him that his shimmer is leaking. She disables the shimmer, revealing the man to be a Graske. The Graske is then killed by a Time Sentinel as Cleo escapes. She scans the device to find out what it is. After the scan completes, Cleo is shocked and attempts to ring the Doctor.

On Zhe's private moon, above Ouloumos, Zhe Ikiyuyu is speaking with Gabby Gonzalez, who is now her apprentice. The Doctor is attempting to repair Marcie while the binary apprentice offers them refreshments. The Doctor says that he won't be able to repair Marcie without a Xenobian matter-phase transmuter. Cindy persuades him to take a short trip in the TARDIS to get one.

The Doctor and Cindy land on Mechma Onzlo III Station, and the Doctor asks Onzlo if he has anything to repair Marcie with. He then asks if Onzlo is okay, since he doesn't look alright. Onzlo explains that his wife Marteek has "changed", saying she is an imposter. The Doctor goes to speak with her, telling Cindy and Onzlo to try look for a transmuter. The Doctor walks up to Marteek, who is standing on a round spacecraft. The Doctor tells her of Onzlo's suspicions, and asks to scan her just to reassure him. Marteek walks into the craft, and tells the Doctor that Onzlo's suspicions were correct, before closing the door. The Doctor runs away as the craft lifts off the ground and chases them, making a sound similar to the TARDIS. Cindy and the Doctor escape in the TARDIS, and Cindy asks him what the craft was. The Doctor guesses it was a chameleon device or a time engine, saying that Marcie tried to tell him about it the last time he was on the station, but he dismissed it. As they track Marteek through the Time Vortex, Cindy tells him she got the transmuter he wanted.

On Aramuko, Noobis is walking with Siffhoni. He tells her that he sent a telepathic message to the Doctor, and that he'd come to Aramuko once he receives it. Despite this, Siffhoni continues to believe that the Doctor, Gabby and Cindy are figments of his imagination.

Back on Zhe's moon, Zhe ends that day's training lesson with Gabby. Gabby walks away and asks the female apprentice whether she had seen the Doctor or Cindy. The apprentice tells her that they had left in the TARDIS, shocking Gabby. She almost loses control of her powers, but Zhe helps her bring them under control. Gabby and Zhe talk for a while, before Gabby leaves while Zhe waits behind to order food.

In the Vortex, the Doctor receives a signal from Cleo. She asks him to come and check the details of the artefact she found, but the Doctor doesn't want to lose Marteek. Eventually he reluctantly agrees, and goes to meet with Cleo. He inspects the artefact, and comes to the same conclusion as Cleo. Cindy asks what the matter is, and the Doctor and Cleo explains that the artefact contains information that Earth will cease to exist within a matter of days. Cindy says that they had seen a future where the Earth survived, but the Doctor explains that the future had been changed and that Earth is going to die.

On Zhe's moon, Gabby is walking alone, talking to herself. She hears a voice, and turns around to see Cindy and the Doctor standing there. They tell her to go with them. Zhe goes to find Gabby, and sees what appears to be the TARDIS. She hears Gabby yelling, and turns to see her being restrained by two Time Sentinels, no longer in their disguises. Zhe dodges an attack from the Sentinels. Gabby tries to tell her to warn the Doctor as she is pulled into the "TARDIS", which flies into the sky, revealing itself as the Red TARDIS.

Part 2
In a red void, Gabby is confronted by Ood Sigma who encourages her to not to trust "them" and to believe in herself and the Doctor. Opening her eyes, Gabby finds that the red is Aspect Red who welcomes her to the Time Sentinels' base of operations, declaring that she will be saved from the Doctor.

Ever the pragmatist, Cindy suggests jumping forward a few days to see how Earth will die and figure out how to undo it only for the Doctor to decide that the box, while genuine, is a trap. And given all the recent chaos they've been dealing with, the Doctor is sure that it's just one part of a much larger design. It's then that a call comes in from Noobis, forcing Cindy to catch Cleo up on the Osirian's change of heart and memory loss. Suspecting that they're being tested, the Doctor decides against walking directly into the trap and instead opts to try and have their foe reveal themselves.

At the base, Gabby is furious. Less so at the kidnapping, or intervention as the Sentinels have chosen to label it, and more that the Time Sentinels have decided to conscript the Red TARDIS, noting that it's a monster that wants to consume all reality. Aspect Blue assures her that they've leashed the Red TARDIS before the Sentinels explain their issue. Recently, the Doctor has cauterized a potential timeline. However, as is the Doctor, the Time Sentinels find him lacking in subtlety. And without any Time Lords, they have to clean up the Time Vortex. The Guiding Aspect, the Cardinal Guardian of the Time Lock, has allowed the Sentinels to use whatever resources required for the mission. With that, Red and Blue strike Gabby with pink lightning, burrowing into her mind.

As the TARDIS hurtles through time, Cindy registers calls coming in from all across the time zones, the Doctor forcing her to ignore them, confident that they're being manipulated. The TARDIS soon touches down on Aramuko with Cleo's presence triggering more of Noobis' memories, and leading Cleo to ask what became of Dorothy Bell. With relative peace, the Doctor asks for a cup of tea so they can compare notes.

As more lightning strikes her, the Sentinels explain to Gabby that, despite all the good he does, the Doctor's actions create ripples. And those ripples could, in theory, damage the time lock surrounding the Last Great Time War. To prevent this, the Sentinels have created a timeline where Earth is destroyed, planning to trap the Doctor inside when he goes to investigate. However, the Doctor refuses to enter the timeline and they want Gabby to act as the new lure. As Gabby points out however, Earth is home to several fixed points in time and destroying it could cause catastrophic damage to the timeline. Unamused, the Sentinels knock her down and begin communing. Realising that their gambit has been found, Aspect Red drops all subtlety and tracks the Doctor down to Aramuko, opting for a more overt strategy.

On Aramuko, Cindy and Cleo catch up and discuss how travelling in the TARDIS changes people. As the topic moves onto unrequited romance, they find solace in each other. Concurrently, the Doctor and Siffhoni tend to Noobis, with Siffhoni being very interested in learning more about the Doctor's travels and character.

Suddenly, Cindy's cry grabs both their attention and everyone runs to the balcony to see a red vortex encroaching on the planet.

Part 3
As Cindy catches up Cleo on the Time Sentinels, the Doctor issues a warning to the absent beings, swearing to defeat them. With a determined expression, the Doctor storms back to the TARDIS, demanding that, over Siffhoni's protests, Noobis be awoken.

On the asteroid, Aspect Blue makes clear his disapproval of Aspect Red's unilateral actions and his overstepping of their authority, warning that the Osirian AI will be looking for them now. As Red waves off these concerns, Gabby attacks him from behind, sending her into his mind for a meeting with the Lock-Keeper, the gestalt entity that all the Aspects make up.

Getting to the heart of the matter, Gabby asks the Lock-Keeper why Red hates the Doctor so much. The Lock-Keeper shows her a memory of Red asking for the Doctor's whole timeline to be unwound, an act that the Lock-Keeper overruled based on how intertwined the Doctor's timeline is with the causal threads of reality. However, the Lock-Keeper did permit Red to take actions to protect the time lock. Red however, did impart on the Lock-Keeper the notion that "creativity is chaos" allowing a horrified Gabby to realise who is really in charge as her eyes glow red. In the real world, a second Aspect Red knocks out both Gabby and the genuine Red, leaving Blue in command who quietly mutters that creativity is not chaos.

On Aramuko, Cindy and Siffhoni guide Noobis into the TARDIS while the Doctor and Cleo reboot Marcie asking the droid to track Marteek's ship, both Cindy and the Doctor recognizing it as Time Lord technology. Marcie soon locates the Sentinels on an asteroid within the Circle of Transcendence. Dismaying at the arrogance of the Sentinels, the Doctor asks Marcie to open a channel.

In an ethereal void, Gabby is confronted by the mysterious voice once again, assuring that help is on the way and awakening her to be greeted by Marteek. As the two compare notes, the Doctor's holographic head appears. Despite Marteek's warnings, Gabby throws herself against the force field, drawing the Doctor's attention and telling him of their plane to trap him. Furious, the Doctor turns on Blue who takes full responsibility for the crisis and orders the maw pulled back from Aramuko, over Aspect White's protests. With the vortex shrinking, Blue asks to speak to the Doctor on urgent business only to be shot in the head by Red who closes the line. As Blue kneels in pain, Siffhoni convulses. Limping over to Gabby's cell, Blue requests her help before he leaves, though not before confirming to Gabby that he's not the mysterious voice she's been hearing.

As the TARDIS touches down on Aramuko, the Doctor scrambles to try and find a way to a close the maw, aware that Red will reopen it, and the redundant timeline that the Sentinels are creating. Using a time cone inverter, the timeline can be sealed off but it will require two time engines. A single TARDIS simply isn't enough. As Cindy and Cleo question how the Sentinels have been keeping such up-to-date tabs on them, the Doctor explains that the Time Sentinels are a failsafe left behind by the Time Lords. Though they act like an unknowable cosmic entity, they're in fact a preprogrammed system. And the Doctor reckons that the system is fallible, asking a nervous Siffhoni if she agrees with that assessment.

On the asteroid, the Red TARDIS materialises in Gabby and Marteek's cell, beckoning them aboard as it dematerialises.

Her number called, Siffhoni sheds her mask to reveal herself as an avatar of Aspect Blue. Reminding the Doctor and Cindy of their encounter on Ancient Gallifrey, which does win him an audience with the Doctor, Blue reveals that he was sent to spy on the Doctor's friends and has come to disagree with the other Sentinels' motives. His time with Noobis and hearing of the positive influence that the Doctor has had on his companions has made him realise that the Doctor is not a deceiver or a charlatan, but the greatest force against evil that exists. Convinced, the Doctor asks about the Red TARDIS, Blue revealing that Red saved it from oblivion and recruited it but before he can say more, an enraged Noobis destroys his head.

As Blue's corpse disintegrates, the Doctor mourns that he truly believed that the Sentinel wanted to help. Shaking away the philosophical thoughts, he inputs the coordinates of the asteroid only for Marcie to detect the Red TARDIS flying towards them at very high speeds.

Ramming speeds.

Part 4
The Doctor snaps at Marcie to create a time cone inverter now that the Red TARDIS is in range. Though Marcie readily does so, she warns that they're now hurtling towards the Sentinels' base in the splinter timeline.

Within the control room, Red tries to have White lock out Blue only for the rogue Sentinel to have gone completely off the grid. When Red orders White to disconnect their Eye of Harmony and instead begin drawing power from the Circle, White balks as the act is outside their jurisdiction. His patience at its limit, Red lays a hand on White and starts corrupting him with a vine pattern. Watching from above, a horrified Blue realises the truth of it all. The Red TARDIS is not under Red's command, he's under it's. When Blue is confronted by the Lock-Keeper, he realises that even the first among them is falling victim to the Red TARDIS, which is why Blue set up a separate power source for himself. Even as all his fellows convulse and are corrupted by the Red TARDIS, Blue runs deeper into the asteroid.

As the two time capusles fall, the Red TARDIS expands its exterior dimensions and slams into the TARDIS, its doors breaching the console room. Demanding an audience, the Red TARDIS opens its doors to reveal Gabby and Marteek, the former using a forcefield to give the Red TARDIS indigestion. At the Doctor's command, Marcie uses the time cone to separate the two time capsules, sending both crashing into the asteroid, the Red TARDIS slamming into the corrupted Lock-Keeper and saving Blue's life.

The fall sends Gabby back into the ethereal void where the voice tells her that the moment is coming before she wakes up again. As ideas are debated, Noobis proposes using the time cone inverter to close both the Circle and the splinter universe at the same time so that the impacts would cancel each other out. As the geniuses prepare to start work, Cleo draws their attention to the Lock-Keeper whose movements are now puppeteered by the Red TARDIS. Cleo, Gabby, and Noobis try to shoot down the spheres that orbit the Lock-Keeper, representing all the Aspects, but fail to make sufficient progress before Blue arrives with an army of himself, granting them a brief respite.

As Blue explains the magnitude of the threat they face, the respite is cut short as an army of Red Sentinels arrive, the Doctor ordering everyone back in the TARDIS. When Gabby runs in the opposite direction, the Doctor chases after her, assuring that he needs her. Touched for a moment, Gabby instructs the Doctor that the Red TARDIS will try again to link dimensional thresholds when the TARDIS activates. Gabby can spare the TARDIS any pain with a dilated temporal ellipse but only if she's on-board the Red TARDIS to act as an anchor. Though agreeing with the plan, the Doctor is left dumbstruck at where Gabby got such knowledge for what she's just said is advanced Time Lord science, not block transfer, certainly not something Zhe could have taught her. Gabby runs to the Red TARDIS, only asking that the Doctor leave open the TARDIS doors for her. As the army of Blues fall, Blue offers to go with Gabby to ensure her safety, wishing both the Doctor and Noobis good luck as the crafts begin launching.

As the two TARDISes fly, the Red TARDIS rants about its victory, how it will open the way for more of its kind to invade N-Space, guiding the Lock-Keeper's form after them. As Marcie establishes a link between the time ships, Noobis uses his mental powers to override the Red TARDIS' commands. The Circle may have been built using Time Lord technology, but it's still an Osirian design, and he orders it to collapse in upon itself. Though the Doctor insists that Gabby jump to him, she refuses, claiming to need a few more seconds to ensure the sealing is complete. Again dumbstruck by Gabby's advanced knowledge, the Doctor screams at Blue to disconnect only for the Sentinel's shield to fail and the Red TARDIS's vines to seize and kill him. As the rupture seals and the time cone inverter shuts down, Gabby jumps but finds herself caught by the gravitational pull, falling into the collapsing singularity to the horror of everyone aboard the TARDIS.

Falling in the void again, Gabby reflects on "the dots." She, along with all the other companions, are the dots that needed connecting. The path they tread, looking out for the Doctor, makes him who he is. And ensures that when the moment comes, he'll be the man who he needs to be. Gabby's fall is then arrested by the voice who reveals herself to be the Moment. Assuring her that everyone was saved, the Moment explains that she's ensuring that the Doctor will be ready for a crucial choice in his future. Recognizing that the Moment is trying to help the Doctor save Gallifrey, the entity drops Gabby off in the TARDIS, a reward for all her help, and advises her to go easy on the Doctor. He's had a rough time recently.

Coming to on the TARDIS' floor, Gabby is greeted by the Twelfth Doctor, who finally left the TARDIS doors open for her. Overjoyed, Gabby hugs her friend who, despite insisting that he's not a hugger, returns the act.

Characters

 * Tenth Doctor
 * Gabby Gonzalez
 * Cindy Wu
 * Cleopatra Hunsicker
 * Noobis
 * Zhe Ikiyuyu
 * Binary apprentice
 * Onzlo
 * Marteek
 * Marcie
 * Time Sentinels
 * Aspect Red
 * Aspect Blue
 * Aspect White
 * Aspect Grey-Seventeen
 * Graske
 * The Moment
 * Twelfth Doctor

Worldbuilding

 * Sarah Jane Smith visited Zhe's moon.
 * Zhe mentions both Dravidian and Manussan food.
 * Gabby "connects the dots" and manifestations of the Doctor's companions past and future appear: Sarah Jane, Turlough, Frobisher, Charley, Martha, Donna, Clara, Bill.

Continuity

 * The Time Sentinels make a reference to Aspect Black, who was a solo operative, like the Doctor. (COMIC: The Tides of Time)
 * Cleo refers to the Tenth Doctor as "Doctor Mysterio". Grant Gordon would give the same name to the Twelfth Doctor. (TV: The Return of Doctor Mysterio)
 * The Moment takes on the form of Ood Sigma. (TV: Planet of the Ood et al.)
 * The Moment takes the form of Bad Wolf and is leading the Doctor on a path to save Gallifrey. (TV: The Day of the Doctor)
 * Due to her time sensitivity, Gabby knows that the Doctor is going to save Gallifrey. (TV: The Day of the Doctor)
 * The Twelfth Doctor is not much of a "hugger" like his past incarnations. (TV: Deep Breath et al.)
 * The Twelfth Doctor later becomes a "hugger." (TV: The Magician's Apprentice et al.)