A shipping magnate’s son receives a confidential letter from his father and doesn’t give it much thought while reveling in his affluent lifestyle during a trip to Shanghai. However, someone is intensely interested in what that letter contains, and "Bob" (Thomas Beck) soon becomes entangled in a complicated scheme. Luckily, the mysterious "Moto" (Peter Lorre), also traveling discreetly on board, notices a tattoo on a …