Set in Amsterdam in the early 1980s. Tegan's cousin is caught up in strange forces while on a backpacking holiday. The Time Lords are worried about the possible return of an old enemy and the only way to stop him is to execute the Doctor.

On the planet Manussa, in an unknown time. It is unknown how or why Tegan has steered the TARDIS here unconsciously. The planet is about to celebrate the 500th anniversary of the expulsion of devious Mara.

In 1816, the Doctor and gang arrive at a villa near Lake Geneva in Switzerland; they plan to soak up the atmosphere as Lord Byron and the Shelleys prepare for a night telling ghost stories, but the villa proves to have ghostly presences all its own.

The Doctor discovers a starship trapped in a time warp over the planet. Meanwhile, public schoolboy and secret alien Turlough crashes his math teacher's vintage car. The Black Guardian makes him an offer.

The Doctor and Sarah encounter Professor Sorenson who plans on transporting anti-matter.

The Doctor and Sarah arrive too late, and a ravenous monster emerges from Zeta Minor.

The Doctor and Sarah continue their efforts to stop the release of deadly anti-matter.

The Doctor realizes not only must he save the universe, but Sorenson, from himself.

After a meeting in space with a group of unseen aliens the Doctor returns to Gallifrey and claims the presidency of the Time Lords. Leela meanwhile tries to work out why he is behaving out of character. At his induction, the Doctor is 'crowned' with a device giving him access to the Matrix. He then arranges for the transduction barriers around Gallifrey to be put out of action by K9. When this is done, his alien 'friends' materialise. They are telepathic invaders called Vardans.

Finding the fourth segment of the Key to Time was simple enough, but holding onto it may be another matter. The Doctor finds himself embroiled in the political games of the planet Tara, where androids complicate the coronation of the planet's rightful Prince.

The Doctor encounters a dragon.

The Doctor meets evil Mr. Kane.