The Syndeton Experiment
Avon hatches a risky plan to take over the planet Syndexia, the last remaining source of the hyperdrive fuel substance called Syndeton. But the already delicate plot is unraveled when Vila gets drunk in a bar on another planet and mentions Syndexia as the crew’s next destination. Vila is only barely rescued by the others as a Federation squadron moves in. Thanks to Vila’s carelessness, Servalan is alerted to Avon’s next destination, yet he presses on. Avon’s concern with Syndexia is not just with the coup to be gained by taking over the supply of Syndeton, either - in so doing, he intends to overthrow Madame Gaskia, Syndexia’s ruler, who once betrayed Avon to the Federation long before he joined Blake. Servalan is interested not only in the power to be harvested from Syndeton, but from its potential as a mind-controlling substance as well, an ability she tests by taking over Tarrant. Before long, the chase is on to find Dr. Rossum, a missing Federation scientist whose research into Syndeton could unlock its dangerous mind-control abilities. Scorpio’s crew finds Rossum first, but at the last minute, Avon insists on conceding this battle to Servalan - and the spoils could be control over every life form in the galaxy.
written by Barry Letts
directed by Brian Lighthill
music by Jeff MearnsCast: Paul Darrow (Avon), Michael Keating (Vila), Steven Pacey (Tarrant), Jacqueline Pearce (Servalan), Angela Bruce (Dayna), Paula Wilcox (Soolin), Peter Tuddenham (Orac / Slave), Judy Cornwell (Gaskia), Peter Jeffrey (Doctor Rossum), Graham Padden (Vledka)
Original BBC Radio 4 broadcast: December 17, 1998
Timeline: this story takes place between The Sevenfold Crown and the fourth season episode Animals.
An unusually vivid nightmare gives Avon a horrifying preview of Servalan’s latest scheme. Using a jewel of alien origin, she can inflict her will upon others in a very limited fashion. A sudden escape from a Federation interceptor leaves Scorpio’s newly-installed stardrive drained. Since the stardrive’s advanced power cells can only be procured from a Federation installation, Avon decides to strike Servalan’s current hiding place, the planet Feron, where she is researching the origins and potential power of her new weapon. Avon and Vila eavesdrop in hiding as a scientist reveals the crystal’s secrets (and then condemns himself to a premature death by admitting that he knows that Servalan isn’t “Commissioner Sleer”). From that moment, the race is on to find a jeweled diadem whose telekinetic and telepathic properties would give its wearer more than enough power to topple the Federation. But when Avon learns that an even more powerful crown, of which the diadem is only a part, could give him the ability to rule the entire galaxy…why stop with just the Federation?
The seventh Doctor is drawn to a jungle world, where he rescues a hapless bystander and discovers an elderly couple nearby. The couple have a unique relationship based on a mutual loathing that seems like it could become murderous at any moment - and they both have very dark secrets to hide. The fifth Doctor, meanwhile, finds himself locked out of the TARDIS, which has materialized aboard a doomed British ship in the North Atlantic. The ship is torpedoed by a German U-boat, and the TARDIS is lost at sea. The Doctor, along with an Irish woman from the British vessel, drifts along with the debris until taken aboard the German sub as a spy. Elsewhere, on the starliner Edifice, the sixth Doctor’s TARDIS arrives, coinciding with an experiment being performed on a time-sensitive creature known as the Temperon. But shortly after the experiment fails, the entire crew - with the exception of its android helmsman and a waitress who appears to have survived through pure luck - is killed, and the Doctor must find out why. Each incarnation of the Doctor is unaware that he is facing the same threat, but in different places and times. And each Doctor has a piece of the puzzle that could save their besieged home planet of Gallifrey.