Parts: 4
Writers: Pip and Jane Baker
Airdates: 7 September 1987 - 28 September 1987
Production Code: 7D

Doctor: seventh
Companion: Mel

Megalomaniac of the Week: the Rani
Creature Feature: Tetraps

Story: The TARDIS crashlands on the planet Lakertya, knocking Mel out cold and causing the Doctor to regenerate. Into the TARDIS marches the Rani, who directs her unseen servant to bring the Doctor to her laboratory. Upon awakening, the Doctor recognizes the Rani, so she is forced to drug him. When he comes round again, thinking he is suffering from post-regenerative amnesia, the Rani has dressed up as Mel in an attempt to persuade the Doctor to work on an experiment for her.

The real Mel, meanwhile, has fallen into the company of Ikona, one of the few Lakertyans on the planet who has not been forced into working for the Rani. But the surface of Lakertya is mined with traps laid by the Rani - notably a spinning bubble that carries its victim into a cliffside before exploding - and her bat-like Tetrap servants roam the landscape armed with netguns.

The Rani is preparing a scheme that will destroy Lakertya and give her control of time itself, and unless Mel and the Doctor can rouse the Lakertyans from their apathy, they may not be able to stop her in time.