A group of palaeontologists have been savagely attacked while carrying out a study of fossilised dinosaur remains in an underground cave system on twenty-fifth century Earth. A party of troopers and Professor Kyle, the only survivor of the attack, are investigating the deaths of her colleagues when they discover the Doctor and his companions at the site of the massacre. The time-travellers are immediately suspected. In trying to establish their innocence and find out who - or what - was responsible for the killings, the Doctor is confronted by an old enemy.

On the serene planet Deva Loka, an expeditionary force from Earth is dangerously out of control. It's not only the peaceful race of the Kinda who are at risk. A gentle stroll in the lush jungle leads the Doctor and Adric to an unexpected confrontation - and puts them at the mercy of a maniac. But it is Tegan, lulled to sleep by mysterious wind-chimes, who comes closest to a danger than threatens not only her sanity but the existence of the whole planet.

Mud, barbed wire, the smell of death.... The year is 1917 and the TARDIS has materialised on the Western Front during the First World War. Or has it? For very soon the Doctor finds himself pursued by the soldiers of Ancient Rome; and then he and his companions are reliving the American Civil War of 1863. And is this really Earth, or just a mock-up created by the War Lords?

Geoffrey Beevers reads this exciting novelisation of a classic TV adventure for the Fourth Doctor. The Doctor is suddenly summoned to Gallifrey, the home of the Time Lords, where his ghastly hallucinations of the president’s assassination seem to turn into reality. When the Doctor is arrested for the murder, a hideous, dark, cowled figure is gleefully watching in the shadows. In a battle of minds, the Doctor faces renegade Time Lord the Master inside a nightmare world created by his old enemy’s imagination.

The TARDIS lands in a primeval forest, and the Doctor meets Leela, a warrior banished from her tribe. He learns that an ongoing war between the Sevateem and the Tesh was instigated by Xoanon, the god they both worship. In reality, an all-powerful computer, Xoanon, is possessed by a desperate madness directly related to the Doctor - one which only the Time Lord can rectify! In order to do battle with Xoanon, the Doctor must escape, not only from the savage practices of the Sevateem but also from the mind-controlling impulses of the Tesh.