The professor and his Son is volume two of the Zradian Chronicles which follows the fortunes of Julian Renfrew, his girlfriend Glorida a fighting Group Leader of the Zradian Women's Rebel Army and Angela Breen. To make his life more difficult the President has put a price on Julian's head and stops at nothing to capture him. To serve his evil ends the President abducts the Professor, and orders the invasion of Earth. To help the Earth's leaders to cope with the sudden invasion of thousands of fanatical enemy troops the Zradian Pair Dart and Drat make contact with the British Prime Minister mistaking him for the most prominent world leader. As a target for the dreaded Polisocs, the political and social police force of Zrad, Richard Byrde with his two bodyguards, Lugs and The Ferret, and his assistant Norman Oliver Braine find themselves landing on Zrad itself through a matter transfer port set in the ruins of a garden shed on a Thames side allotment. Meanwhile the Earth's armed forces on all five continents are battling against the Zradian invaders. The incompetence on both sides creates a special kind of chaos which the robot, panicking now its home and rodent family is under threat, becomes locked in a cyber battle with the Zradian and Earth military forces. Julian and the women's rebel army are creating their own chaos on Zrad and although Julian is always terrified he becomes a rebel hero. In contrast, Angela Breen who constantly questions her Christian beliefs, creates her own form of terror for the President's forces. The story is now filled with characters such as Colin Hicks and his urban thugs, Tzu Wu, the Chinese patriarch and his Thousand Kung Fu artists, detectives Bates and Fish, ex-Inspector Sherman Holmes and Blard the Barmy and his twin who set out to create mayhem amongst the President's forces. Bates and Fish, who can rarely complete one sentence on their own, never lose site of their mission to arrest Julian are also aware of the Mad Fireman Weddell whose desire to slice Julian with an axe motivates him to converge on the young hero. Even the mad robot is having its problems and desperately needs its creators, the devious and corrupt Pair Clard and Dracl, to help solve its problems and fit it with new parts.