In September 1941, the great German physicist Werner Heisenberg travels to Copenhagen to meet with his mentor Niels Bohr. Heisenberg asks Bohr to carry a message to British and American scientists: if they slow their development of an atomic bomb, he, as head of the German program, will do the same. In response to what they regard as a morally offensive and unworkable offer, the Allies set up a special committee that appears to accept Heisenberg's offer while undertaking a program of systematic deception. They will misinform Heisenberg about Allied intentions, reinforce his scientific errors, and feed him disinformation. Sticking to the program isn't easy, and the Allies' soon learn that their lies are challenged by Nazi espionage and unexpected--even shocking--scientific developments.