Cory, the world's leading authority on RNA (ribonucleic aid) the brain substance in which memory is stored -- is approached by the CIA and asked to conduct a weird and dangerous experiment: to remove the RNA from Hauser, a dying German scientist who has defected from the Russians, and inject it into another man in the hope of releasing the German's secrets. At first, Cory is appalled. But Slaughter, the CIA man, has thought of everything -- even to providing a suitable 'subject' for the bizarre experiment.

The experiment succeeds -- but to an extent which neither Cory nor Slaughter could anticipate. For it is not only Hauser's memory that is transferred. With it go his obsessions, his dreams, his emotions, his character...gradually, insidiously. And there begins the bitter struggle as Hauser's memory tries to posses its new mind -- the mind of a man who is acutely aware of what is happening to him. The dead German's monomaniacal quest for vengeance -- that soon involves security elements from both East and West in a thrilling international chase -- and the final chilling confrontation between the man possessed by Hauser and the object of Hauser's search combine to make an enthralling, suspenseful and utterly credible science fiction novel which is a fitting successor to Donovan's Brain.