'You are an artificially constructed human being, a mobile gathering device.' That is what the computer's metallic voice tells Tanner when it releases him from his cell. Naked, unarmed, with no memory to guide him, he emerges into a savage world, into the ruins of Manhattan in the 23rd century where wild animals roam and men have become cannibals in a frantic struggle to survive. Who has unleashed this chaos upon the world? Has Tanner really been dispatched to gather facts to help save the tragic remnants of humanity? Or is he to be the final instrument of its destruction?