The battle-scarred War Doctor decides he must use an ancient Timelord device to end the Last Great Time War in an act of genocide, and the device has him glimpse his future to understand the consequences before he presses its big red button.
On Arcadia, Galifrey's "safest city," soldiers stand in watch during the Dalek planetary siege.
The weary Eighth Doctor chose to help but not fight in the Last Great Time War, but is finally forced to reconsider upon his return to Karn.
The Doctor, with a robotic Master as his initial companion, reluctantly finds himself fighting aliens in Lancashire, England, side by side with UNIT.
The Master attempts a modified diabolical plan to destroy the Doctor for good, but the wind quickly breaks, leading to catastrophic problems for both.
Referencing largely unelaborated events, the Master is captured and executed by the Daleks, who task the Seventh Doctor to take the remains home to Gallifrey, but the conscious remains trigger events that quickly lead to the emergence of the Eighth Doctor. This renewed Doctor must fight the after effects of regeneration and the self-resurrected Master.
The Seventh Doctor and his companion, Ace, find themselves in the middle of a diabolically nonlinear trap of renegade Timelady, The Rani, involving past Doctors, their companions, and the denizens of London's East End.