The Doctor's curiosity is aroused by a darkened remote lighthouse.

An alien stalks survivors.

As the number of victims grows, the Doctor is still at a loss as to the identity of the killer.

The Doctor and Leela are forced into a battle for survival against the alien killer.

An antimatter monster wipes out a geological expedition when the leader tries to bring antimatter into a parallel universe. With Tom Baker.

Reptilian Silurians wake from hibernation and try to wipe out humanity by introducing a deadly plague and raising Earth's temperatures.

The Brigadier insists upon exploring the caves.

The Tardis lands on an apparently deserted spaceship orbiting the Earth in 1983.

In 1977, Tegan and Nyssa think the decaying body they've discovered is the Doctor's.

Both the '77 and '83 Brigadiers exist in the same time zone, and their meeting could cause a temporal catastrophe.

Mawdryn blackmails the Doctor into agreeing to surrender his eight remaining lives to release the mutants.

The Doctors share an adventure across time and space; an ancient battle reaches a devastating conclusion.

The Swampies decide that Kroll must be appeased with human sacrifice, and guess who they select as the victims.

Kroll embarks on a rampage and Thrawns efforts to defeat the monster only make things worse.

The Doctor begins a perilous mission to save all humankind from destruction.

The Doctor and his companions are trapped on Zeos, which has been programmed to self-destruct.

As the forces of evil amass, the Doctor, Yaz and Dan face perilous journeys and seemingly insurmountable obstacles in their quest for survival.