In November 1955, a merchant vessel was found drifting 600 miles off course in the South Pacific, partially submerged but afloat, with fuel in the tanks and food in the holds, yet all 25 passengers and crew, four tons of cargo, and the life rafts had vanished. The most baffling part: the ship was designed to be virtually unsinkable. This episode unpacks the locked-room mystery of the MV Joyita.

We trace the ship's colorful history from Hollywood yacht to Navy patrol boat, and the fateful 1943 repair using galvanized iron that triggered 12 years of hidden corrosion. We follow desperate Captain Dusty Miller's reckless departure on one engine, the swamped engine room, the radio wired to a distress channel but cut by a painted-over break, the bloodstained bandages, and the theories from mutiny to Cold War paranoia.

• Why cork insulatio ...