The Doctor is feeling confident: this time the TARDIS has landed on Earth; in England; in 1963. But when he and his companions Susan, Ian and Barbara venture outside, they are soon lost in a maze of ravines and menaced by gigantic insects. However, the insects are dying - every living thing is dying.... Meanwhile, in a cottage garden on a perfect summer's day, the man from the Ministry arrives to put a stop to the production of DN6, a pesticide with the power to destroy all life-forms.

When the TARDIS materialises on an alien spacecraft, the commander of the ship - the reptilian Monarch - invites the Doctor, Adric, Nyssa and Tegan to continue their journey to Earth in his company. Monarch's hospitality even extends to a generous offer to liberate the time travellers from the shortcomings of their bodies and replicate them as androids - so much more practical. Although Adric finds this proposal extremely attractive, the Doctor has good reason to be suspicious of Monarch's motives....

John Leeson stars in this exciting novelisation of a classic adventure for the Fourth Doctor - and the introduction of K9. A mysterious cloud drifts menacingly through space, and the Doctor becomes infected with the Nucleus of a malignant Virus that threatens to destroy his mind. Meanwhile, on Titan, human slaves prepare the Hive from which the Virus will swarm out and infect the universe. In search of a cure, Leela takes the Doctor to the Bi-Al Foundation, where they make an incredible journey into the Doctor’s brain in an attempt to destroy the Nucleus. 

Geoffrey Beevers reads this action-packed novelisation of a Third Doctor television adventure. Seven months after it left Mars, there has still been no radio communication with the Probe Seven spacecraft or the astronauts inside it. Back on Earth concern is mounting, and eventually a recovery capsule is sent up to rescue the astronauts. But when the capsule returns to Earth, it is found to be empty. As the Doctor and Liz investigate, they discover that the interior of the capsule is highly radioactive.

Eminent scientist Emil Keller has developed a revolutionary new process for the treatment of hardened criminals. His invention, the Keller Machine, is being heralded as a major scientific breakthrough. But Professor Keller is in truth the Master, and the Keller Machine is much more than a mere machine. Soon the Doctor, Jo, the Brigadier and UNIT are involved in a bitter struggle with the Master, an alien mind parasite, and a diabolical scheme to plunge the world into a Third World War....