Paul Schumann is a German-American living in Brooklyn in 1938 and a hitman for the mob. When he is arrested he is taken to an unnamed Colonel in intelligence and given a choice. Either go to jail for life or help his country. The US has discovered that Germany is secretly rearming and that the architect of this rearmament is a man named Reinhardt Ernst, a senior Nazi official and one of Hitler's right hand men. The Colonel wants Schumann to pose as a member of the Olympic team, travel to Berlin and assassinate him. Schumann agrees, goes to Germany and takes a room on the Tiergarten where he works with Morgan, an American expatriate to plan the assassination. There he meets Marlene, an idealistic former journalist and Webber, a black marketeer and fellow gangster, both finding themselves being persecuted by the Nazis. Meanwhile, Willi Kohl, a Berlin criminal investigator is trying to solve the vicious murder of a man connected to the Americans, in the Tiergarten, while trying to keep the SS from interfering. Two German brothers and their sister have been arrested for smuggling their parents - two anti-Nazi professors - out of Germany and are struggling to survive and trying to plan an escape to England. With the opening ceremonies of the Berlin Olympics as their backdrop, all these stories intertwine with twists and turns and a thrilling denouement.