Michael Sheard

The excavation of an ancient Egyptian tomb unleashes the Evil Sutekh, last of the Osirans, imprisoned millennia before by his own people. Sutekh attempts to build a time/space bridge between his tomb prison and the English manor house that was the home of the unfortunate archeologist who opened the tomb.

Nyssa and Tegan follow the trail of blood away from the Cabinet, trying to find the Doctor while avoiding the feathered warriors in the forest. They eventually spot the Doctor some distance away, but although they call out to him he doesn't recognize his own name. The warriors take the Doctor into Castrovalva with them, but Nyssa and Tegan arrive seconds too late.

Realising the true nature of Castrovalva's reality, The Master, seeing all is lost, flees to his TARDIS. The Doctor and his companions flee from the city, but who will survive as the city collapses in on itself...

At Stangmoor Prison, the Doctor and Jo watch a demonstration of the Keller Machine which can extract evil impulses from criminals. But the experiment goes wrong and a man dies.

The Doctor and Ace return to the England of 1963, the same time as the Doctor and Susan used to live in a scrap yard in Totters Lane. Returning to the school where Susan studies, the Doctor discovers that all is not as it should be. It soon becomes clear that a war between two Dalek factions is being fought, while they both seek a device the Doctor had hidden on Earth on his last visit.