AllMovie

"Texas Lightning" is the nickname of professional cardsharp Jeannie Lowry (Julie Sommars), who hires Magnum (Tom Selleck) as her bodyguard during a big-time poker game on a luxurious yacht. It soon develops that Jeannie is using the game as a cover for a planned burglary of the adjacent yacht belonging to a shady character named Matt Thompson (Jack Hogan), and that there's some high-stakes espionage activity in the air. The result of all this skullduggery finds Magnum and Jeannie running for their lives on a not-so-deserted island. This is a heck of a way for Magnum to be spending his birthday!