The second fragment of prosecution evidence in the Doctor's trial is his adventure on Thoros Beta:
The Doctor and Peri visit Thoros Beta, the home planet of Sil. Peri is impressed with the fluorescent beaches and water. When they eventually find a way off the beach they are attacked by a genetically enhanced creature.
The Doctor and Peri find that things are not well on the planet. Peri is disgusted to find that the Doctor has brought her to Sil's home planet, and Sil is less than impressed also. The Mentors have a problem: Their leader's brain is expanding, and soon it will be too large for his skull, which will kill him.
They have brought in a scientist, Crozier, to find a way to relieve Kiv's suffering. The Doctor is tested for viability as a host for Kiv's brain. After being subjected to one of Crozier's machines the Doctor starts to act selfishly, even to the point of betraying Peri.
The Doctor's allegiance is unknown - he seems to be helping the Mentors, although he pretends it is a plot and helps a trapped warrior king to free the Thoros Alphans that are being held for experimentation. Chaos breaks out, and Peri is taken by Crozier, and found to be the perfect donor, although Sil is not happy about the choice; but it would save Kiv.
The Time Lords think that the Doctor has gone too far, and allowed the situation to get out of hand. To this end they take him out of time. They also trap King Ycarnos in a time bubble, and release him when the time is right.
Inside the laboratory Kiv's mind has been transplanted into Peri's. As Kiv awakes, Ycarnos is released. Seeing that Kiv now inhabits the body of his Queen, he kills her ...
Regular castPeri Brown: Nicola Bryant;
Guest castThe Valeyard: Michael Jayston; The Inquisitor: Lynda Bellingham; King Ycarnos: Brian Blessed; Sil: Nabil Shaban; Kiv: Christopher Ryan; Crozier: Patrick Ryecart; Matrona Kani: Alibe Parsons; Frak: Trevor Laird; The Lukoser (Dork of Kanval): Thomas Branch; Tuza: Gordon Warnecke (7-8); Mentor: Richard Henry (8);
Uncredited cast: The Jury: David Backe, John Buckmaster, Rodney Cardiff, James Delaney, David Eynon, Peter Gates Fleming, Gary Forecast, Leslie Fry, Bob Hargreaves, Johnny Lee Harris, Jack Horton, Lew Hooper, Derek Hunt, Guy Matthews, Ken Pritchard, Roy Seeley, John Shereton, Kenneth Thomas, Leslie Weeks, Geoff Whitestone, David Wild, Llewellyn Williams; Mentor: Deep Roy; Extras: Tony Annechi, Sholamar Bowers, Roy Brent, Ray Charles, Jonathon Coudrille, James Dublin, Veronique Chomillo Edwards, Lorence Ferdinand; Khristyne Kashvilli, Ronnie King, Belinda Lee, Wendy Millward, Lee Montgomary, Mike Mungarvan, Jacqueline Noble, Kevin O'Brien, Ferdinand Orako, Eugine Paul, Madnine Rainer, Bill Richards, Gavin Robuck, David Rogue, Edward Runifitt, Joe Santo, Steve Sparling, Lewis St Just, Alan Warner, Dale Warren, Russell West, Des Williams;
|BBC 1||644||Part Five||Sat 4 October 1986||5:45 pm - 6:10 pm||4.8M||76th|
|BBC 1||645||Part Six||Sat 11 October 1986||5:45 pm - 6:10 pm||4.6M||87th|
|BBC 1||646||Part Seven||Sat 18 October 1986||5:45 pm - 6:10 pm||5.1M||87th|
|BBC 1||647||Part Eight||Sat 25 October 1986||5:45 pm - 6:10 pm||5.0M||84th|
Telscombe Cliffs, East Sussex;
Television Centre Studio 1;
Bloopers and mistakes
Episode 8: A bulb blows as the TARDIS dematerialises.
Notes and trivia
Nicola Bryant leaves at the end of Part Eight.
Although the whole season was shown on television as one long 14 part story, there are four segments with production codes, and the programme has been novelised in this form.
Planet of Sil;