The Baron and Cordelia are at the Macao docks checking a shipment of antiques. A missing crate leads to Cordelia witnessing a murder on baord a cargo ship. When she is held prisoner Mannering has to stow away on the ship. They meet an undercover CIA agent working as one of the crew who tells them about the ship's mysterious cargo and its secret destination. The CIA agent is killed and Mannering forced out into the open.

With the ship arriving at the island to deliver its cargo, Mannering learns of the plot to steal an American space capsule. Via the ship's radio he alerts the US Navy of the plot. He and Cordelia escape and they must think up a plan to stop the robbery and hope that the Navy can get to them in time to assist.