When four capital ships vanish, Admiral Nelson and Commander Van Wyck are sent to investigate. They find an island where Nelson removes a dagger from a skeleton which happens to be the captain of the Amsterdammer, the Flying Dutchman, and is then cursed. Van Wyck is in reality the first mate who killed the Captain. His plan is to kill Nelson with the dagger so that he can be free and Nelson will take his place.

When a top secret Neutron Bomb begins leaking radiation, Seaview crew men begin disappearing and those who haven't begin seeing things. The Seaview is racing the clock to fire or disarm the missile before it explodes.