Posted to Washington during the Cold War, Donald Maclean is using visits to his wife in New York for access to the Atomic Energy Commission, passing information to Soviet contact K. Melinda wants him to stop and CIA man Angleton is suspicious after Soviets explode an atomic bomb. Kim Philby goes to America to head off Angleton. Guy Burgess is also in Washington and is dangerously out of control. Maclean returns to London and does the bare minimum for Moscow. Angleton has traced an atomic leak to possible suspects including "Homer", Maclean's code name. Philby can't protect Maclean any longer, Moscow insists he's recalled along with Burgess. Anthony Blunt orders Burgess to accompany Maclean to Moscow but doesn't explain that neither will be coming back.