Aided by his two assistants Jamie and Victoria, the Doctor lands the TARDIS on Telos, last resting place of the infamous Cybermen. There he discovers a band of archaelogists on a secret expedition to unearth the reason for his old enemies' extinction. In the underground shadowy depths, they find the icy tomb. A whole army in hibernation. A threat to no one, if the temperature remains low. But if the traitor in their midst gets his way, things could really heat up.

Time itself is in peril! The Time Lords and UNIT find themselves besieged by a mythic figure from the Time Lords' past hell-bent on destruction. The only way to defeat him is to break the First Law of Time and let the Doctor help himself — literally...

Death stalks the fogbound streets of Victorian London: young women are going missing, horribly mutilated bodies are found floating in the Thames and criminal gangs terrorize the innocent. At the heart of this tangled web sits the mysterious Li H'sen Chang, sorcerer and hypnotist, and his grotesque sidekick Mister Sin. The Doctor dons deerstalker hat and cape to seek out the sinister force lurking in the shadows of the metropolis, for the Talons of Weng-Chiang are reaching out to shred the human race.

The Daleks draft the Second Doctor into distilling the Human Factor. Once implanted, it will make the Dalek race invincible. Jamie's faith in the Doctor is stretched to the limit as the Doctor appears to be collaborating with the Daleks. The Doctor has a few tricks up his sleeve, but then again so might the Daleks.

The Doctor, Jamie and Zoe arrive on an unnamed planet. At first believing themselves in the midst of World War I, they realise it to be one of many War Zones overseen by the War Lords, who have kidnapped large numbers of human soldiers to form the greatest army the universe has ever seen. At the helm of this plot is the War Chief, another renegade Time Lord like the Doctor. The creeping realisation sets in that the Doctor cannot solve this problem alone, and that his days of wandering may be at an end...

The future. The material needs of people are tended by the Machine, which makes their environment, in vast tunnels beneath the earth, comfortable and safe. But if the Machine stops, what then?

The future. The TAU-mode shuttle carries passengers to Australia through the earth's crust. When a routine TAU-shuttle becomes entombed in solid rock miles under the earth, the only means of rescue is the experimental LAMBDA-mode shuttle; which its creator is unsure about.

Level 7 is the deepest and the safest level in a nuclear bunker. The nerve centre of the government is based here. But how safe is it?

The Master, an old adversary of the Doctor, has arrived on Earth to destroy humanity with the aid of the Nestene Consciousness and their army of Autons and killer plastic daffodils - unless the Doctor, joined by new assistant Jo Grant, can stop them.

The Master, in the guise of Professor Thascalos, has constructed at the Newton Institute in Wootton a device known as TOMTIT - Transmission Of Matter Through Interstitial Time - to gain control over Kronos, a creature from outside time. The creature is summoned but proves to be uncontrollable.