Nuclear weapons make the world more dangerous than ever before. The destruction of Hiroshima and Nagasaki in 1945 by atom bombs is hailed for ending the Second World War, but the long-term effects of radiation are discovered years later. To ensure parity with the US, Stalin puts his scientists to work and four years later the Soviet Union explodes its first nuclear bomb, starting an arms race between the superpowers in which peace is maintained through the doctrine of mutually assured destruction. Governments take steps to protect its citizens through civil defence. Popular movements calling for nuclear disarmament appear in force from the late 1950s, and the expensive arms race is eventually stopped in the 1980s. Nuclear power supports economic growth and technological advances, but the Chernobyl disaster in 1986, as well as the impact of nuclear testing in Utah and Bikini Atoll, keep the public at large distrustful of nuclear science. The opening scene shows the preparation and execution of the world's first nuclear test in New Mexico, United States.