Duplicate Incident

The Duplicate Incident was the Time Lord designation for the event in which the Daleks, supported by Dalek duplicates, retrieved their creator Davros from the Prison Station. (TV: Resurrection of the Daleks, PROSE: Dalek Combat Training Manual)

In 4590, (PROSE: Resurrection of the Daleks) the Daleks had recently lost their war with the Movellans after the androids developed a virus which attacked Dalek mutants. The Supreme Dalek led an expedition to rescue Davros from human custody, which he'd been held in for 90 years, in the hopes of him devising a cure for the virus. (TV: Resurrection of the Daleks)

Background
The Daleks came into conflict with the Movellans, a race of androids. As both sides relied on logical battle computers, a stalemate ensued. In an attempt to break the deadlock, the Daleks returned to Skaro to recover their creator Davros, who was dormant in the ruins of the Kaled dome following the Dalek Prime's attempt to exterminate him centuries earlier. Their operation was disrupted by a rival Movellan expedition and the arrival of the Fourth Doctor and Romana. The Doctor and Romana helped the Daleks' human slaves rise up and take Davros into their custody in suspended animation. (TV: Destiny of the Daleks)

Davros was transferred over to the Earth Protection Corps. While en route a ship transporting him rescued the Tenth Doctor and Anya Kingdom and came under attack by a Dalek saucer, causing it to crash land on Kembel. The Movellan Prime Rocket commanded by the First Movellan pursued them, capturing the Doctor and Davros, whilst a secret faction of Daleks on Kembel emerged from hiding. (AUDIO: The Dalek Defence) Davros feigned forming an alliance between the Daleks and Movellans, actually using the agreement to infect the Movellans with a virus. The Doctor prevented the virus spreading beyond Kembel and sent the Prime Rocket away before its crew could reboot. At the same time Earth Protection Corps forces arrived on Kembel, defeating the Daleks and recapturing Davros.

Inspired by his experience with Davros, the First Movellan decided to investigate a virus to use against the biological component of the Daleks. (AUDIO: The Triumph of Davros)

For 90 years, Davros remained in human custody in suspended animation, eventually being kept on a Prison Station. The Daleks meanwhile lost the war with the Movellans due to them successfully developing a virus which affected Dalek mutants. (TV: Resurrection of the Daleks)

Conflict
In 4590, (PROSE: Resurrection of the Daleks) the Supreme Dalek led an expedition to invade the Prison Station to rescue Davros, in hopes of him providing a cure for the virus. At the same time, the Daleks stored vials of the virus in a warehouse in London in 1984, linked to their battlecruiser by a time corridor, and infiltrated human governments with duplicates.

Using troopers led by the mercenary Lytton alongside drones, the Daleks successfully invaded the Prison Station and awoke Davros. Meanwhile the Doctor's TARDIS became caught in the time corridor and arrived in the warehouse, with the Fifth Doctor, Tegan Jovanka and Turlough meeting a bomb squad that had been called there after the vials of Movellan virus were mistaken for explosives. After Turlough fell into the time corridor, they were attacked by a Dalek, which they managed to destroy.

At liberty in the station, Davros used the virus research the Daleks has tasked him with as a means to secretly convert humans and Daleks to his cause, eventually building up a small army loyal to him alone. He had come to believe that his original Daleks had failed in light of their defeat, and sought to create a new race of Daleks loyal to him in its place. At the same time the Doctor travelled through the time corridor in his TARDIS in search of Turlough however was swiftly captured after being betrayed by Stien, a Dalek duplicate within the bomb squad who had accompanied him. The Daleks announced he would be duplicated, along with his companions, with the duplicate tasked with the assassination of the Time Lord High Council on Gallifrey, (TV: Resurrection of the Daleks) intended as revenge for the Time Lords' plot to destroy them at their creation. (AUDIO: The Dalek Conquests) The duplication process was interrupted by Stien, having overcome his Dalek conditioning with the Doctor's aid.

On Earth, the bomb squad was attacked by Dalek duplicates who had infiltrated them, including two disguised as policemen, and Daleks, resulting in many deaths. Tegan escaped the massacre by reaching the time corridor, reuniting with the Doctor and Turlough. The Doctor took his companions back to his TARDIS and then went to confront Davros, intending to kill him. Davros talked the Doctor down with promises to redesign the Daleks and they were interrupted by Dalek agents. The Doctor escaped whilst Davros unleashed his converted forces on those loyal to the Supreme Dalek.

The rival Dalek forces fought in the warehouse on Earth whilst Davros unleashed a sample of the Movellan virus at the station. As he made for an escape pod however, Davros began suffering the effects of the virus himself. The Doctor reunited with his companions at his TARDIS, which had been pulled back to the warehouse, and was contacted by the Supreme Dalek, which bragged of the Dalek duplicates still in position of Earth. The broadcast was interrupted by Stien detonating the station and docked battlecruiser in revenge against the Daleks, (TV: Resurrection of the Daleks) though the Supreme Dalek did escape alive, (PROSE: Resurrection of the Daleks) as did Davros. (AUDIO: Davros)

Aftermath and legacy
In the immediate aftermath of the incident Tegan decided to stay on Earth, having grown tired of all the death that accompanied travelling with the Doctor. (TV: Resurrection of the Daleks) Decades later in 2006, the Doctor would meet her again in Brisbane. (AUDIO: The Gathering)

Having deemed his original creations failures, Davros would subsequently seek to found his own faction of the Daleks on Necros under the guise of the "Great Healer". The original Daleks were alerted to his scheme and arrived to capture him taking him back to Skaro for trial for his crimes against the Daleks. (TV: Revelation of the Daleks) The meddling of the Sixth and Seventh Doctors enabled Davros to escape to Spiridon where he turned an entombed Dalek army of 10,000 drones to his control, with which he conquered Skaro and was proclaimed Dalek Emperor, beginning the Imperial-Renegade Dalek Civil War. (COMIC: Emperor of the Daleks!)

Lytton was left stranded on Earth along with two policemen duplicates, (TV: Resurrection of the Daleks) eventually being employed by the Neomorph Cybermen to aid their scheme to change history in 1985 to avert the destruction of Mondas. Lytton, however, would side with the Cryons who opposed the Cybermen on Telos, an act which would result in his death, leading the Sixth Doctor to reflect that he had never misjudged someone as badly as he had Lytton. (TV: Attack of the Cybermen)

After their memory of the Doctor was wiped from the Pathweb, the Daleks forgot, amongst other incidents, who had foiled the assassination of the Time Lord High Council. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)