In 1939 the scientific world is buzzing. Research on the atom is advancing fast and everyone wants to be the first to succeed in uranium fission. Governments closely follow these advances, while international tensions are rising. The race for the atomic bomb is launched. Unlimited funds are injected into scientific research: Hitler attracts the best physicists by giving them financial and human resources hitherto unknown and the National Centre for Scientific Research (CNRS) is established in France. But to control nuclear fission, the French and the Germans alike absolutely need heavy water. This rare resource is produced in a single factory in Vemork, a small Norwegian town, which then becomes a major strategic issue. From 1939 to 1944, the Allies lead several secret operations to recover the stocks of heavy water, and to prevent Hitler getting his hands on them.

This documentary, constructed as a true historical thriller, returns for the first time to this little known, but nevertheless crucial episode from the Second World War.

The beginning of World War II is now nearly 80 years in the past. Before it is too late, it is important to retrace a decisive struggle that was one of the war’s greatest stakes, and the first step of a long nuclear arms race.