The TARDIS lands on Fang Rock island at the start of the 20th century.
The Doctor seals the survivors inside the lighthouse but discovers that the creature might be with them.
The Doctor devises a desperate plan to defeat the alien and repel the approaching Rutan mothership.
Deep space, 5000 AD. An Earth supply shuttle is infected by a strange sentient space-born virus.
Leela and Lowe take the Doctor to the Bi-Al Foundation for help.
Miniaturized clones of the Doctor and Leela are injected into his brain.
The Nucleus, now grown to human size, is determined to spawn and take over the Galaxy.
A mysterious skull that is older than mankind is exerting a deadly influence on those around it.
The Doctor realises that an ancient horror from the mythology of his own people is manifesting at Fetch Priory.
The Doctor and Leela take a trip in the TARDIS to discover the truth about the ancient evil from the dawn of time.
Thea has become the Fendahl Core and Stahl realises that he is out of his depth.
Pluto has been made habitable and turned into a giant factory where the ruthless Company exploits its workers.
The Doctor is taken prisoner by the Gatherer and sent to the Correction Centre.
The Doctor is free but Leela has been captured by the Gatherer and is sentenced to a grisly death.
The Others launch a full-scale uprising against the Gatherer and his Inner Retinue.
The TARDIS lands on a spaceship which is crewed by the survivors of the planet Minyos.
Tthe Minyan survivors discover what they have been searching for. But their arrival is not welcomed.
The Doctor and Leela attempt to penetrate the Citadel of the Seers to rescue Idas's father.
The Minyans are eager to recover the race banks that they have waited so long to find.
The Doctor returns to Gallifrey and abruptly stakes his claim on the Time Lord presidency.
The Doctor is made president of the Time Lords and immediately orders K9 to lower the planet's defences.
The Doctor has betrayed his own people and enabled a Vardan invasion of Gallifrey.
As the Vardans finally fully materialise on Gallifrey, the Doctor prepares to spring his trap.
The Sontarans have taken control of the Capital on Gallifrey and intend to use the power of the Time Lords.
Stor, the Sontaran leader, finally gains access to the TARDIS in search of the Great Key of Rassilon.