Jesse McDermitt lives on an isolated island in the Florida Keys where he runs a charter fishing business. Retired from the Marine Corps for six years, he wants nothing more than to relax, fish, dive, and enjoy the laid-back lifestyle of the islands.
Russ, his former Sergeant and old friend, dies unexpectedly in a mysterious scuba diving accident and Jesse becomes suspicious. His friend's son comes to south Florida to ask Jesse if he would take him to a remote reef to spread his father's ashes and the two men discover that Russ was murdered. They agree to hunt down the psychotic killer together, unaware that their manhunt will lead them to a Caribbean terrorist cell.
Meanwhile, a beautiful woman has returned to the Keys on a manhunt of her own, distracting Jesse with the idea that he could finally leave his warrior past behind. Surviving a powerful hurricane puts everything on hold as a top secret government agency tries to recruit him into their fold.