The TARDIS lands on a planet on the verge of total annihilation as it drifts too close to the three suns which its orbits.

After being born in prison, Moll Flanders wends her way through the top and bottom of 18th-century English society, has five husbands and many male and female lovers, travels to America and back again, and in general discovers all that is cruel and sweet in life.

Irish lads send an ad to the Miami Herald inviting fit and enticing women, between the ages of 20 and 21, to live in their isolated Donegal village. The whole town knows about the ad, and it sharpens everyone's sense of the opportunities for happiness already at hand. Kate, a publican with a young daughter, is separating from her husband and catches the eye of a bachelor sheep farmer. Kieran the butcher realizes that his assistant Siobhan is comely, and then he discovers she's fiery as well. Ollie sends off for Dutch skin magazines that the village postmistress won't release to him. The men, and women, find counsel in their movie-loving priest. Will anyone answer the ad?

Zina, the daughter of Leon Trotsky by his first wife, is undergoing freudian analysis in Berlin in the 'thirties. Meanwhile Trotsky is in exile in Prinkipo having been driven from power by Stalin. The Nazis rise to power in Germany and Austria and Zina commits suicide.

Vicki is telling one of her stories.

Nocturne is a taut chamber drama, set in a musty suburban estate to which a pretty but drab-looking woman returns upon the death of her mother, who in flashback we discover was a fiercely proper and dominating woman. Eichhorn's depressed reveries are abruptly interrupted with the unexpected arrival of a pair of hitchhikers, amoral, free-spirited young lesbian lovers seeking shelter from the rain.

In London, a traitor is selling information. In Moscow, a Yorkshire cloth salesman is approached by the KGB, who believe he has more to sell than cloth.

On the planet Dido, the Doctor, Ian and Barbara meet two survivors from a crashed spaceship who are terrorised by the monster Koquillion.

The TARDIS crew take up residence near Rome in 64AD, where Ian and Barbara are kidnapped by slave traders, and the Doctor's imitation of Maximus Pettulian sees him taken to the court of Emperor Nero where he inadvertently plays a part in deciding the course of history...

On the planet Vortis, the Doctor and his companions aid the butterfly-like Menoptra in their battle against the parasitic Animus and its mind-controlled minions, the ant-like Zarbi.