They've been stranded on Earth for 20 years, so Zygon commander Kritakh, and his second, Torlakh, have had plenty of time to re-create their world. The trouble is that Kritakh, aka engineer Mike Kirkwood, has lost his sense of purpose. Can Torlakh, aka mass murderer Bob Calhoun, get him back on track. Enter sexy Psychiatrist Lauren Anderson, first, to be tempted by her innermost desires and then to face her greatest challenge. Can a violent heart really be tamed by love and what is the ultimate price to be paid?

When Dr Lauren Anderson agrees to Thomas Mordley testing his experimental new drug Cyberon on her brain damaged patients she expects little benefit. But Cyberon is going to revolutionize medicine and maybe even the world.

The Nestenes have made the final connection.

Two years have passed since the Nestene creature vanished from UNIT's top secret Warehouse... Suddenly and without warning the Nestene strikes, once again using Autons as its deadly foot soldiers. As mysterious UNIT operative Lockwood struggles to unearth the Nestene plan, he finds himself drawn to remote Sentinel Island. There, the population have been caught up in a bizarre frenzy of religious activity. Lockwood is joined by Natasha Alexander, a new scientific advisor with her own, sinister agenda. To defeat the Nestene menace they must both face the terrifying power of a creature from before the dawn of Mankind...

In a top-secret UNIT warehouse Dr Sally Arnold is studying a Nestene energy unit with little success. Until she subjects it to cosmic signals that activate it and it awakens several dormant Autons stored in the facility.