The Doctor is threatened on all sides by unseen danger.

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.

An ancient evil - the Malus - exists within the church at Little Hodcombe.

The TARDIS arrives on Fang Rock, a small island off the English coast, around the start of the 20th Century. The Doctor and Leela seek shelter at a lighthouse where the island's only inhabitants - Ben, Vince and Reuben - operate the recently-installed electric lamp to warn ships off the treacherous rocks.

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.

Murder interrupts the Doctor's plans.

The Doctor meets a giant rat.

In a South Yorkshire city, Ryan Sinclair, Yasmin Khan, and Graham O'Brien are about to have their lives changed forever as a mysterious woman, unable to remember her own name, falls from the night sky.

The ideas of time travel; "The Grandfather Paradox;" "The Butterfly Effect;" "Doctor Who."

The Doctor and Romana brave the terrors of Eden.