The quiet of Longboat Key, Florida, is shattered when an old man is shot to death and his murderer is killed while fleeing the police. Strange documents in German and Arabic are found in the killer's car then an old friend of the murdered man disappears.
The island's only detective, Jennifer Diane (J.D.) Duncan, receives a text message with a picture taken that morning of a college friend whom she thought was dead. Matt Royal and J.D. are pursued by men who would do them harm, and Matt's best friend, Jock Algren, a shadowy operative of the U.S. government's most secretive intelligence agency, comes to visit the island.
As the mystery deepens, a ragtag group of devious and dangerous characters intrudes on the lives of the islanders, creating a kind of havoc unusual for a sun-splashed island full of retirees and beach bums. Matt, J.D., and Jock rush to find the answer to why one old man was killed and another disappeared, the meaning of the photo sent to J.D. of her almost surely dead college friend, and why somebody is trying to kill them.