The following version of this book was used to create this study guide: Sandford, John. Ocean Prey. G.P. Putnam’s Sons, 2021. Kindle Edition.

As the narrative begins, an off-duty Florida Coast Guard officer named Barney Hall, is on his boat with his wife and child off the coast of Fort Lauderdale when he sees a Mako boat engaged in suspicious activity. He informs the Coast Guard watch officer who sends three Coast Guard officers to investigate. They find the Mako. However, unbeknown to them, the occupants have just retrieved a large amount of heroin that a freighter ship dropped in the water. When the Coast Guard officers identify themselves to the occupants of the boat, one of the men on the boat kills them. The Mako races to the dock, and the occupants begin to unload the heroin. Barney kills one of the men on the Mako as the culprits burn the boat and escape. Barney receives a medal for his work. However, months later, the case is still unsolved. The circumstances cause a Florida Senator to convince U.S. Marshal, Lucas Davenport, to work with the FBI to solve the case.

In the past, Lucas has worked with two other marshals, Bob and Rae. Rae is not available to work with him now because she is spending time with her ailing mother. So, Lucas goes to Florida with Bob. They work with the FBI who is headed by a man named Dale Weaver. Their plan is to shake things up by talking to drug dealers, and anyone who might know about the operations on the boat, and offer them deals in exchange for information. They set about doing this. In the process they get closer than they realize to the culprits, who are members of a New York Mafia family. The key players in Florida are Michael Behan, Jack Cattaneo, Matt Lange and Marc Regio. Doug Sansone, who is based in New York, is the head of the organization. In order to get rid of Lucas and Bob, the mobsters hire hit men and devise a plan that will eliminate Lucas, Bob, and Don Romano, the leader of a rival Mafia family.

Lucas, Bob, and Weaver fall for the bait. They place surveillance on Romano. When it looks like something is happening, Bob and Lucas go to make an arrest. However, unbeknown to the criminals, the FBI is with them. Weaver sees the hit men. His actions save Lucas, but Bob dies.

The events upset Lucas because Bob was both a co-worker and a friend. He also worries that Rae will blame him for Bob’s death. He tries to figure out what went wrong and concludes that they were set up. Romano supports the theory by telling them that Sansone wants to get rid of him. He tells Lucas that if he is going after Jack Cattaneo, he is moving in the right direction. Lucas leaves Florida to regroup.

He returns with a new plan. There are still a lot of drugs in the water. Cattaneo and his men have not been able to retrieve them because their previous diver disappeared after the shootings. Lucas convinces his friend, Virgil Flowers, to go undercover as a weed-loving diver with a criminal record. Rae, who is now on the case and does not blame Lucas for Bob’s death, poses as Virgil’s girlfriend. Virgil and Rae go to Florida and get Cattaneo‘s attention. He hires Virgil to retrieve the drugs.

The Florida connection plans to use a hearse to transport the heroin to New York. Lucas goes there and convinces the FBI to not take the drugs when they arrive. He wants to follow the money to capture Sansone. His plan is to offer one of the dealers a deal if they help them capture Sansone with the drug money. He knows he has to be careful to not endanger Virgil and Rae’s lives. They decide to arrest a dealer who they think might cooperate with them. They have a problem when he does not. They know that they cannot give him the lawyer he has requested because the lawyer will inform Sansone of the arrest. So, they hold him. Then they find another likely candidate to take the deal. This one does. He gives them the information they need and also helps pass money that will connect Sansone to the drugs. He tells them that they have a problem if the man they have in custody did not call Sansone at the appointed time.

In Florida, Virgil and Rae are already in trouble. Virgil is diving, and Rae is on the boat when Cattaneo receives a call saying that there is a problem. Cattaneo, Regio, and Lange conclude that Rae and Virgil all the leaks. Rae is prepared for trouble because Lucas was able to alert her to a potential problem. When Regio tries to shoot her, she kills him. She holds the others at gun point. Virgil returns. They go to the port. When they arrive, the authorities greet them and arrest Cattaneo and Lange who discover that Virgil and Rae are U.S. Marshals.

In New York, Lucas and his team arrest Sansone and his wife. However, back in Florida, Behan has escaped. Lange tells Rae and Virgil that Behan has a plane. They find the plane as it is about to take off and Virgil stops it by shooting the nose which causes one of the tires to go flat.

The investigation brings an end to Sansone’s organization. Virgil and Rae tell Lucas that they love working with each other. Virgil goes home to his family. Lucas returns to his family and suggests that they take vacation during spring break. His wife thinks that it is a great idea but warns that they have to wait and see because there is a dangerous new virus. Lucas thinks that medical technology can take care of it.