On February 13, 1950, a U.S. Air Force B-36 bomber flying a simulated nuclear strike mission ran into icing over British Columbia and began losing engines. Before ditching, the crew jettisoned their Mark 4 atomic bomb over the Pacific coast and detonated its conventional explosives at altitude, then bailed out into the wilderness. The film traces the search for the wreckage, the survivors' ordeal in the snow, and the decades-long question of what happened to the bomb's uranium core, whether it was destroyed in the air or still lies somewhere in the mountains of British Columbia. Interviews and archival material lay out the Cold War context that made a flight like this routine: a mock mission over restricted airspace, treated as unremarkable until the aircraft itself became the emergency. The film follows investigators and historians who have tried to pin down the wreck site over the years, weighing official Air Force accounts against the physical evidence recovered from the crash. It stays with the practical mystery: where the components went, and how much of the story the government has actually told.