Whilst in flight the TARDIS is attacked and lands on the planet Lakertya. The force of the landing knocks Mel. The Rani and a Tetrap enter the TARDIS. She orders the Tetrap to leave the girl and take the Doctor. As it picks up the Doctor he starts to regenerate.
Whilst the Doctor lay unconscious in her laboratory the Rani continued her work, using a Lakertyan, Sarn, to get a figure from Earth's history into a cubicle. The Rani is present when the Doctor re-gains conciousness. Even though he is suffering from post-regenerative amnesia the Doctor recognises the Rani. in an effort to get away he stumbles, and Sarn goes to his aid. She is pushed out of the way, and threatened, by the Rani. The Rani calls for Urak, the Tetrap, who fires a net over the Doctor. Whilst the Doctor is confused she injects him with a solution to increase his amnesia.
Sarn, fearing for her life, flees the Rani's laboratory and onto the surface of Lakertya. Also on the surface is Ikona, another Lakertyan, carrying the unconscious Mel. When Mel recovers she struggles, break free, and makes a run for it. Whilst she is running she comes face to face with Sarn. Sarn is frightened and runs in another direction straight into one of the Rani's traps. Mel watches as Sarn is captured in a bubble. The bubble rises then explodes.
The Rani has been watching the death of Sarn, and orders a Tetrap to reset the trap. The Rani sends the Tetrap to look for Mel whilst she disguises herself as Mel. The Rani uses the disguise to convince the Doctor that the laboratory they are in really is his, and is in need of repair. Believing her the Doctor starts the repairs.
Ikona catches up with Mel. Ikona thinks that as the Doctor and Mel arrived from outer space they must be friends with the Rani. He ties Mel's hands and plans to offer her as a hostage in exchange for their leader, Beyus, who is held by the Rani. Mel convinces Ikona she is not the enemy when she saves his life as he steps on a trap. Ikona lets Mel go, and she sets off to find the Doctor.
Startled by the sound of rock fall, caused by a tetrap searching for her, she stumbled onto a trap. Mel screams as the bubble floats over a cliff... and lands gently in water. Ikona sees the bubble and goes after it. Seeing it in a pool he starts to pull out a mechanism, hoping that it will not explode.
Inside the laboratory the Doctor has found the cause of the problem. A panel wasn't strong enough to resist heat radiation. The Rani says she can find some better material, and leaves. In the mean time Ikona leads Mel to the Rani's control centre. Inside she finds her way into the laboratory. The Doctor distrusts Mel, thinking she is the Rani, and Mel distrusts the Doctor as he has changed. Mel feels for the Doctor's pulse, and finds two. The Doctor feels for Mel's pulse and feels one.
Even though there is only the Doctor in the laboratory she realises the Doctor knows the truth. With Beyus's uncharacteristic help the Doctor is able to escape. Mel, unfortunately, is captured by a Tetrap and taken back to the Rani. The Doctor has stolen something from the Rani, and she offers to exhange Mel for the equipment. The Doctor agrees, but the Rani only sends a hologram of Mel.
The Doctor has no choice but to return to the Rani's base where he learns the truth. The Rani is trying to use a missile to destroy an asteroid of super dense strange matter. The only thing that could destroy it is strange matter. The Rani uses the Doctor, and other figures from Earth's history, to come up with a substitute. The Doctor's influence starts to impact the current minds, and the Rani has no choice but to let him go.
The Rani also has a huge brain to help come up with the formula. The Rani plans to use the explosion to alter Lakertya's atmosphere using Helium Two to produce a time manipulator. When the brain speaks a forumula and gets the answer wrong the Doctor blurts out the correct answer. The Rani is ecstatic when the brain says the forumula has been found. Whilst she is entranced the Doctor and Mel escape.
They make their way back to the Lakerytan pleasure dome where the Rani has effectively imprisioned them by tagging them with explosive tags. Mel, with the Doctor's prompting, is able to remove a tag and show the Lakertyans how to remove the other tags. The Doctor asks Ikona to keep all the tags.
As the Rani is loading a rocket with molten Loyhargil (her name for the substitute created from the formula provided by the Doctor), the Doctor starts to place the tags around the brain. Reluctantly leaving Beyus to complete the task the Doctor sets about stopping the Rani's missile countdown. The Rani, approaching her TARDIS, is dismayed when the countdown stops. When the Doctor appears she manually explodes all the tags, destroying the brain. She also manually fires the missile.
Whilst everyone is looking at the missile firing the Rani escapes in the TARDIS, to become a prisoner of the remaining Tetraps. On the surface the Doctor reassures the Lakertyans that the delay in lift off means the missile will miss the target - even though he is not entirely certain it will.
Regular castMelanie Bush: Bonnie Langford;
Guest castThe Rani: Kate O'Mara; Ikona: Mark Greenstreet; Beyus: Donald Pickering; Urak: Richard Gauntlet; Sarn: Karen Clegg (1); Faroon: Wanda Ventham; Brain Voices: Peter Tuddenham (3-4), Jacki Webb (3-4); Lanisha: John Segal (3);
Uncredited cast: Lakertyans/Tetraps/Geniuses: Arland, Suzanne Britten, Russell Brook, Mark Carroll, Tricia Clark, Paul Cottingham, Les Derrick, Ian Durrant, Karen England, Helen Garton, Amanda Gray, Christopher Holmes, David Ianson, Cenydd Joeenz, Mandy Lesley, Ricardo Mulhall, Mike Mungarvan, Russ Murray, Tom O'Leary, Paul Page-Hansen, Oscar Peck, Penny Rigden, Steve Rome, Sara Wishart, Andrew Woodman;
|BBC 1||654||Part One||Mon 7 September 1987||7:35 pm - 8:00 pm||5.1M||71st|
|BBC 1||655||Part Two||Mon 14 September 1987||7:35 pm - 8:00 pm||4.2M||85th|
|BBC 1||656||Part Three||Mon 21 September 1987||7:35 pm - 8:00 pm||4.3M||85th|
|BBC 1||657||Part Four||Mon 28 September 1987||7:35 pm - 8:00 pm||4.9M||86th|
Westdown Quarry, Cloford Quarry and Whatley Quarry, all near Frome, Somerset;
Television Centre Studio 1; Television Centre Studio 8;
Bloopers and mistakes
In one scene the Rani orders Urak to remove Mel's body from the TARDIS, to which Urak replies that Mel is no longer aboard the TARDIS. However, the Rani had been watching as Sarn, who had been scared by Mel, stood on a bubble trap, so the Rani should have already known.
Notes and trivia
The ninth title sequence (designed by Oliver Elmes) and fourth theme arrangement (by Keff McCulloch) are used.
Episode 1: Part One opens with a pre-titles sequence that ends with the Doctor's regeneration. Due to Colin Baker's unavailability for the episode Sylvester McCoy dons a wig to be the sixth Doctor - when Urak turns the Doctor over his face is blurred.