Loss of the Exterminator

The loss of the Exterminator was a critical development leading to the close of the Second Dalek War, representing total disaster for the Dalek Empire's war effort. It occurred on Hurala circa the 2580s, "over forty years" after the First Dalek Incursion.

Engineered by the Tenth Doctor after his failed mission to Arkheon, the incident was not a large-scale engagement involving the Earth Empire but its consequences were enormous. The destruction of the prided Exterminator was reported by Space Major Jon Bowman to have plunged the rest of the Dalek Fleet into chaos, and ended any possibility of the Daleks utilising time travel to win the war. (PROSE: Prisoner of the Daleks)

Mission to Arkheon
After learning from a Dalek prisoner that the Daleks intended to weaponise the Arkheon Threshold to change human history, the Tenth Doctor urged Jon Bowman and his team of bounty hunters aboard the Wayfarer to travel to the ruins of Arkheon and locate the Threshold before the Daleks did.

However, the Doctor severely misjudged the situation. The Daleks had already established an immense prison facility on Arkheon and were using slaves to uncover the Threshold. The Wayfarer crew were all captured, with the Doctor and Bowman both identified as highly valuable prisoners. Dalek X, the Dalek Inquisitor General, was dispatched by the Supreme Dalek to interrogate them. He arrived on Arkheon aboard the Exterminator, which, due to these developments, had been diverted away from the main Dalek Fleet during its ongoing engagement against the Earth Empire.

Despite their incarceration, the Doctor took advantage of the Daleks' limitations in time travel technology. They lacked the means to properly breach the Threshold. The Doctor slyly pushed Dalek X to the conclusion that his TARDIS would be suitable for their needs. Sensing the opportunity, Dalek X agreed to bring the Doctor and the Wayfarer crew under heavy guard to Hurala, where the TARDIS had been left. The Daleks' Temporal Research Team also accompanied them in order to examine the TARDIS. (PROSE: Prisoner of the Daleks)

Escape on Hurala
Locating the TARDIS at Lodestar Station 479, the Doctor pretended to have lost the TARDIS key on his previous visit to Hurala. By diverting the Daleks away from the TARDIS and deeper into the station, the Doctor intended locate and detonate the astronic fuel left over in the silos from before the planet was abandoned by Earth explorers. Effectively, the station itself was a potentially "ginormous bomb" and was the Doctor's primary reason for luring the Daleks there.

His chance at escape came when Cuttin' Edge recognised one of the Daleks as the individual who had executed his friend Scrum. In a revenge-fuelled rage, Cuttin' Edge managed to overpower and destroy some of the guards even as he was cut down. The Doctor, Bowman and Koral took the opportunity to flee as Dalek X and the Command Dalek from Arkheon ordered the Elite Guard Daleks and Assault Daleks to hunt the escapees down.

Escaping through the vents, Bowman armed himself with a leftover ion bolter and magnetronic condencer which made short work of some of his pursuers. Dalek X realised he had been tricked and discovered what the Doctor intended to do, so he gave chase himself and tracked the Doctor down at the silo controls. While elevating, his underside was vulnerable to attack and he was immobilised by Koral's claws. Bowman emptied the ion bolter at point blank range into Dalek X's neck grille and shoved the flaming Inquisitor General from the gantry into the depth of the station.

Badly injured, Bowman volunteered to stay behind to prevent the safety override function from activating while the Doctor and Koral returned to the TARDIS. The Command Dalek and the others reached Bowman seconds before the explosion. The reappearance of the TARDIS allowed Bowman the chance to escape. It demateralised as the fuel detonated. The remaining Daleks were totally vaporised.

The blast was powerful enough to blow the planet open. The Exterminator, hovering above the station, withstood the first shockwave but its force fields buckled in such close proximity to the astronic blast. It crashed onto the surface, igniting a second series of explosions with took out the other support vessels. All hands onboard were lost. The explosion was visible from as far as seven light years away. (PROSE: Prisoner of the Daleks)

Aftermath
The diversion of the Exterminator left the Dalek Fleet under strength. When it failed to return to the front, Earth Command was able to punch a hole in the Dalek lines. The fleet fell into disarray and Earth was able to begin pushing back the Dalek advance. With the loss of the Temporal Research Team, the Supreme Dalek was also forced to abandon any further efforts to use time travel to win the war.

Earth Central was informed of the developments by Bowman, who, having been designated a criminal for desertion, received a full pardon. Earth Command organised a squadron to attack the Dalek prison on Arkheon. Bowman was offered the chance to command the mission but he refused, choosing instead to retire, settle down with Koral and re-establish contact with his his parents. Earth's attack was successful, with all the prisoners liberated, and the Arkheon Threshold sealed by the Doctor.

Dalek X was the only Dalek to survive the confrontation on Hurala, shielded inside a crevice opened up by the blast. His casing was wrecked, and while astronic radiation thrown into the atmosphere sustained the Dalek mutant, it also meant the planet was placed under radiation quarantine with a communications seal. The Doctor returned to Hurala to find Dalek X and inform him of the latest developments in the war. The Supreme Dalek had left Dalek X for dead and was never likely to forgive the Inquisitor General for all he had allowed to happen should he ever return, while the quarantine was likely to last around 5,000 years. Dalek X congratulated the Doctor in his "total" victory but warned that, with the Doctor's failure to kill him, he now would eventually return and hunt the Doctor down. The Doctor assured Dalek X that he would be waiting for him and left him along on the planet. (PROSE: Prisoner of the Daleks)

The Second Dalek War thereafter drew to an "untidy conclusion" and soon "fizzled out". (PROSE: Deceit)