The Doctor, Jamie and Carstairs manage to return to the 1917 zone only to be captured by Smythe, who orders the Doctor executed.

To prove his loyalty to the Aliens, the Doctor is ordered to reprocess his friends while the Security Chief finally uncovers evidence of the War Chief's treachery.

The TARDIS is drawn to the planet of the Time Lords where both the Doctor and the War Lord are placed on trial.

The storm-lashed planet Karn. Near a graveyard of crashed starships, the demented surgeon Solon hides in his castle, the last acolyte of the Time Lord despot Morbius. He only needs one final item to make his master live again... and then the Doctor and Sarah arrive...

The Doctor is captured by the Sisterhood, and Sarah Jane is blinded freeing him. The Doctor has no choice but to go back for a cure, unaware that he is leaving Sarah Jane in the hands of a treacherous Dr. Solon and the renegade Time Lord Morbius.

While the Doctor goes to confront the Sisterhood to seek a cure for Sarah Jane's blindness, Solon realizes that he must transfer Morbius' brain into a new body before it is too late.

Morbius lives once more, but as a rampaging beast. The Doctor is forced to ally with Dr. Solon to bring him to heel, but the two disagree about what should happen to Morbius.