In 1946, the US Navy assembled nearly a hundred surplus warships at Bikini Atoll for Operation Crossroads, detonating atomic bombs against them to test whether modern fleets could survive nuclear war. This film follows a modern expedition diving on the sunken remains, from the carrier USS Saratoga resting upright on the lagoon floor to the Japanese battleship Nagato, once flagship of the Pearl Harbor attack fleet. Divers and marine scientists examine corroding hulls, live ordnance still lodged in the wrecks, and coral now growing over gun turrets, while footage from the original 1946 tests shows the mushroom clouds and shockwaves that sank or crippled the fleet. Interviews cover the radiological legacy left in the water and sediment, and what monitoring today shows about lingering contamination. The expedition combines archival test footage with underwater cinematography of the ghost fleet, tracing both the physical decay of these ships and the human history of a Pacific atoll turned into an open-air nuclear testing ground.