The Doctor and Sarah arrive safely back on Earth—or do they? Why does the mysterious solder march straight over a cliff, and then reappear unharmed? Why are they attacked by sinister mechanics with built-in guns for hands? Why is a picturesque country village at first deserted, then filled with mindless zombies? And why are the Doctor and Sarah's best friends trying to kill them? Will they be in time to defeat the deadly Kraals and their terrifying android invasion of Earth?

The TARDIS materialises on a remote island, set in a sea of acid, on the planet Marinus. The Doctor, Susan, Ian and Barbara meet Arbitan, keeper of a vast computer which rules and balances the gentle life of Marinus. Yet peace on the planet is threatened by the sub-human Voord, who wish to take control of the Conscience. Arbitan enlists the travellers to find the five crucial Keys of Marinus in various locations across the planet. Thus begins a series of terrifying adventures for the Doctor and his friends, who must find the Keys if they wish to ever to see the TARDIS again.

Through a Space-Time Visualiser the Doctor and his companions are horrified to see an execution squad of Daleks about to leave Skaro on a mission to find the TARDIS and exterminate the time travellers. Eluding the Daleks on the barren planet Aridius the Doctor and his friends escape in the TARDIS. But this is only the beginning of an epic journey. As they travel through space and time, they try to shake off their pursuers by making a series of random landings - but the Daleks don't give up easily. This is a chase to the death... Maureen O'Brien, who played Vicki in the original Doctor Who TV serial, reads John Peel's complete and unabridged novelisation, first published by Target Books in 1989.

The TARDIS crewmembers have taken a break from their adventures and are enjoying a rest in a luxury villa. But, in the gory grandeur that is Imperial Rome, things don't stay quiet. If the time travellers can save themselves from being sold as slaves, assassinated by classical hit-men, poisoned by the evil Locusta, thrown to the lions, maimed in the arena and drowned in a shipwreck, they still have to face the diabolical might of the mad Emperor Nero. As if that wasn't enough, they also discover that, although Rome wasn't built in a day, it burnt down in considerably less time.

The TARDIS materialises on board a dark and silent spaceship. As the Doctor, Susan, Ian and Barbara penetrate the craft's eerie gloom they come across what appears to be the bodies of two dead astronauts. But the astronauts are far from dead, and are living in mortal fear of the Sensorites, a race of telepathic creatures from the Sense-Sphere. When the lock of the TARDIS is stolen the Doctor is forced into an uneasy alliance with the aliens. William Russell, reads Nigel Robinson's unabridged novelisation.