Glamorous astronaut/test pilot Kelly Wood survives what appears to have been an in-flight encounter with a World War II-era Mitsubishi Zero fighter. She reports the phenomenon to Oscar Goldman and Steve, who are in the control tower, but the men can only see Kelly's plane on the radar screen. Kelly flames out and apparently crashes. But a search turns up no trace of her 15-million-dollar aircraft, the XJ-7, and Kelly is found with her parachute unopened. Believing Kelly's story, Steve sets out to solve the mystery and discovers a fantastic plot to simulate Bermuda Triangle-like disappearances of top-secret aircraft.