In a hearing on his appeal against the revocation of his security clearance, physicist Julius Robert Oppenheimer looks back: on his beginnings, his private life and, above all, on the time when he is assigned scientific leadership of the Manhattan Project during World War II. At Los Alamos National Laboratory in New Mexico, he and his team are to develop a nuclear weapon under the supervision of Lt. Leslie Groves. Oppenheimer is proclaimed the "father of the atomic bomb," but after his deadly invention is used momentously in Hiroshima and Nagasaki, the barely jubilant Oppenheimer is plunged into serious doubt. In another hearing, Lewis Strauss is to be confirmed as Secretary of Commerce in President Dwight D. Eisenhower's cabinet. But soon the issue is his relationship with Oppenheimer after the war. For Strauss headed the U.S. Atomic Energy Agency, which was advised by the physicist. As Oppenheimer increasingly opposes Strauss and an arms race with Russia and argues for international control of nuclear energy, the physicist's old ties to communism come up again....