Time Destructor Incident

The Time Destructor Incident was the Time Lord designation for the attempted Dalek conquest of Earth's solar system in the year 4000. (TV: The Daleks' Master Plan, PROSE: Dalek Combat Training Manual)

Background
Over the course of five hundred years, the Daleks gained control of over seventy planets in Ninth Galactic System and forty more in the constellation of Miros. (TV: Mission to the Unknown (TV story)) In the 40th century they turned their attention back to Earth, coming into frequent conflict with the Space Security Service (SSS) charged with maintaining humanity's security. (PROSE: The Outlaw Planet, COMIC: Sara Kingdom: Space Security Agent, AUDIO: The Destroyers) This included a new invasion of Earth which met with defeat due to the actions of SSS agent Sara Kingdom. (COMIC: The Brain Tappers)

In 3950, (AUDIO: Neverland) Mavic Chen was elected Guardian of the Solar System. He began a secret mining operation of taranium, a rare mineral found on Uranus, (TV: The Daleks' Master Plan) as he was seeking a replacement source of energy for space travel, as Earth's empire was currently dependant on the Great Clock which bent spacetime to aid travel. In 3999, the Great Clock was destroyed due to the meddling of the First Doctor, Steven Taylor and Sara Kingdom, who had time travelled from a later point in the conflict to come. This hastened Chen turning to more radical means. (AUDIO: The Guardian of the Solar System)

Conflict
In 4000, Space Security Service agent Marc Cory travelled to Kembel to investigate reports of Dalek presence at the planet, without informing his superiors of his suspicions. He discovered the Daleks were forming an alliance, known as the Galactic Council, with various powers from Outer Galaxies against Earth, with the intent of invading the solar system. Marc recorded a message for Earth warning of his discovery but was found and exterminated before he could send it. (TV: Mission to the Unknown)

Guardian of the Solar System Mavic Chen agreed to join the Daleks' alliance in secret, supplying taranium that the Daleks needed to construct the Time Destructor. Chen planned to betray the Daleks as soon as he had the weapon, intending to send a fleet at Venus to destroy the alliance. Chen believed he would have an inevitable rise to greatness as "First Ruler of the Universe", and had allies on Earth supporting his scheme, including the head of the SSS, Karlton.

Chen travelled to Kembel to deliver the taranium to the Galactic Council, with his arrival coinciding with two SSS agents, Bret Vyon and Kert Gantry, crash landing on the planet after travelling there in search of Marc Corey. Kert fell victim to a Dalek patrol whilst Bret escaped, encountering the First Doctor who had just arrived on the planet in his TARDIS along with Steven Taylor and Katarina. Despite the Daleks' efforte to flush out the intruders by setting Kembel's jungle alight, the Doctor and Bret were able to infiltrate their city. Whilst Bret, Steven and Katarina went to hijack a ship so Bret could reach Earth, the Doctor posed as delegate Zephon at the Galactic Council meeting where Chen presented the taranium core. The Doctor stole it and escaped with his companions in Chen's own ship, the Spar. The Daleks subsequently exterminated Zephon for his failure.

The Daleks pursued the Spar, using randomiser to disable the controls of the ship and eventually force land it on Desperus with a Dalek ship in hot pursuit. Despite an attempt by prisoners stuck on the planet to hijack the vessel, the Doctor and Bret managed to effect repairs takeoff again. A prisoner from Desperus, Kirksen, revealed himself onboard however and held Katarina at knifepoint to force them to travel to the nearest planet, Kembel, ignoring their protests of the danger there. Katarina opened the airlock she and Kirksen, sending herself and her captor out into space, sacrificing herself to ensure the others might reach Earth. (TV: The Daleks' Master Plan) Katarina's body was eventually recovered from space by River Song. (AUDIO: Companion Piece)

Alternate timeline
In an alternate timeline accidentally created when the Second Doctor's TARDIS collided with that of the First Doctor in the Time Vortex, the First Doctor never arrived on Kembel, instead crashlanding on Urbinia. This resulted in the Daleks successfully developing the Time Destructor, which they deployed to devastating success during the Harvesting of Urbinia. The Second Doctor negated these events by using his TARDIS to avert the collision. (AUDIO: Daughter of the Gods)