A US coast guard finds only a woman still alive aboard a shipwreck. She tells her rescuer what happened and soon, they find themselves trapped in a mysterious part of the ocean known as Satan's Triangle.

An American coast guard pilot and his partner, Haig (Doug McClure) answer an SOS, and arrive at a derelict ship. When Haig boards the ship, he finds 3 dead bodies and 1 survivor; Eva (Kim Novak), cowering in the cabin. When the pilot tries to lift Haig and Eva off the boat, the line snaps, plunging them both into the ocean. After they swim back to the boat, the pilot tells Haig he must return to base because he's running low on fuel. Eva and Haig make the best they can, having to spend the night on the boat, during which time she tells the story of the storm and why this strange part of the ocean is called Satan's Triangle.—Thomas Veil