When several young girls are found dead, left hideously aged and void of blood, Dr Marcus suspects vampirism. He enlists the help of the Vampire Hunter. Mysterious and powerful, Kronos has dedicated his life to destroying the evil pestilence. Once a victim of its diabolical depravity, he knows the vampire's strengths and weaknesses as well as the extreme dangers attached to confronting the potent forces of darkness.

Astronauts rescued from a mission to mars are kidnapped when they arrive back on earth. They seem to have been irradiated, and can now kill people merely by touching them. But the Doctor discovers the astronauts have been replaced with Alien ambassadors who are being forced to behave in a hostile manner. With The Doctor traveling to the alien mother ship, and Liz kidnapped, The Brigadier is left wondering who to trust.

The adventures of The Doctor, a time-traveling humanoid alien known as a Time Lord. He explores the universe in his TARDIS, a sentient time-traveling spaceship. Its exterior appears as a blue British police box, which was a common sight in Britain in 1963 when the series first aired. Along with a succession of companions, The Doctor faces a variety of foes while working to save civilizations, help ordinary people, and right many wrongs.