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 agents alongside drones the Daleks successfully invaded the Prison Station and awoke Davros. Meanwhile The Doctor's TARDIS became caught in their 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. They were attacked by a Dalek, which they managed to destroy. (TV: Resurrection of the Daleks)

Aftermath
Having deemed his original creations failures, Davros would subsequently seek to found his own faction of the Daleks on Necros. 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 the entombed Dalek army to his control, founding his own Dalek faction which conquered Skaro and proclaimed him Dalek Emperor, beginning the Imperial-Renegade Dalek Civil War. (COMIC: Emperor of the Daleks!)

Lytton remained stranded on Earth, eventually being employed by the Cybermen to aid their scheme to change history in 1985 to avert the destruction of Mondas. (TV: Attack of the Cybermen)