The film stars Kirk Douglas as Dr. Rolf Pedersen and Richard Harris as Knut Straud, along with Ulla Jacobsson as Anna Pederson.

The Norwegian resistance sabotage the Vemork Norsk Hydro plant in the town of Rjukan in the county of Telemark, Norway, which the Nazis are using to produce heavy water, which could be used in the manufacture of an atomic bomb.

Rolf and Knut sneak out of Norway on a passenger steamship to Britain that they hijack so they can deliver microfilmed plans of the hydroelectric plant to the British, who are impressed by the information.

Besides this sequence, the raids (Operations Grouse, Freshman and Gunnerside) and the final attack are filmed on-site, with mountainous and snowy Norwegian locations serving as a backdrop.

The movie was originally titled The Unknown Battle and was to have starred Stephen Boyd and Elke Sommer and be written by Ben Barzman.

Despite mainly sticking to the factual evidence, some scenes in the documentary, like the film, were partly dramatised, focusing more on the survival skills involved in the operation.

The same story was also covered in the 1948 Franco-Norwegian film Kampen om tungtvannet (La bataille de l'eau lourde — "The battle for heavy water").

In 2015, the Norwegian Broadcasting Corporation showed a TV series called Kampen om tungtvannet (also known as The Heavy Water War or The Saboteurs) based on the events.