Two years after World War II ends, Tim, who survived the Nazi bombing of London, becomes very sick on poor boarding school rations. He is sent to Germany to join the rest of the family in a village on the outskirts of Hamburg. His father is the main witness in a war-crimes trial. Tim is fascinated by the ruins of Hamburg. In the attic of the house they live in he discovers a very powerful set of biculars. Through the biculars Tim explores the ruins. At school Tim takes on the class bully. An explosion occurs. The main sewer is damaged. The smell is awful. As if things can't get worse the class teacher takes a dislike to Tim. The bully strikes. Tim retaliates with dire results. Things go from bad to worse. Tim finds himself befriending a German boy who could be a thief. Does he live in the ruins? Tim rescues the boy, makes a discovery and acquires a dog. The Nazi officer who is to go on trial escapes. A German bomber pilot calls at the house. And finally the story reaches a dramatic climax in the ruins and a mystery is solved.