Kallie Davis travels to St. Charles Island to search for her missing brother, Andy, who disappeared one night while out in his boat. The shark haunting the offshore waters presents a challenge, but so does Mark Bennett, the new dive master at Villa Marie, the resort owned by Andy and his wife, Leona. Mark offers to aid Kallie in her search, but she's reluctant. Something about him just doesn't add up. Plus, her troubled past makes trusting difficult.
Undercover investigator Mark Bennett has his own reasons for wanting to find Andy. He intends to stick close to Kallie, in case she discovers something useful, or Andy contacts her. But he doesn't want any personal involvement. Risking his heart is as dangerous as losing his cover.