At the end of the 1940s, the Soviet researcher Sakharov is in charge of the hydrogen bomb project, while in the United States, two scientists from Los Alamos, Teller and Oppenheimer, are also working on its elaboration. All over the world, people are preparing to take refuge in nuclear shelters in case of attack: the hydrogen bomb would be able to inflict a thousand times more damage than the atomic bombs dropped on Hiroshima and Nagasaki.