Greg and Colleen Sullivan and their two children Alison and Nick arrive on a late flight to Barbados. A shuttle van pulls up and they are invited to hire the driver to take them to their destination.
Exhausted, the family enters the van. The unsub offers them all complimentary bottles of water. They drink it and three of them fall immediately unconscious. Colleen tries to wake them up and then becomes alarmed when the unsub continues driving to an unknown location.
Section Chief Mateo Cruz tasks two BAU units (one domestic and one international) to work together on the abduction. He informs them that this is the third family who've been kidnapped, and that the previous two vacationing families were killed.
Hotch's team is joined by an international BAU unit headed by Jack Garrett. The members of his team are Lily Lambert, Russ Montgomery (Monty), and Matthew Simmons.
Cruz tells them all that there is pressure to find the family quickly, as the unsub typically kills the family shortly after abducting them.
Monty is Garcia's IT specialist counterpart on the international team. The only difference between them is that he has to be the liaison with affected family members, because the rest of his team is usually located in a different country.
Hotch and Lambert spot someone they think is the unsub and they give chase and catch him but it turns out he's just selling cocaine and hasn't been there long enough to be the unsub.
The team's profile of the unsub is that his victims are surrogates for his own family. He's playing the part of the outraged and abused oldest son.
The teams determine the unsub has the family on a boat, and that he is using water torture on the dad and whipping him with his belt. It turns out he is holding the family captive on a boat.
Meanwhile, Greg Sullivan uses a knife to free himself. He attacks the unsub while his son frees his wife and daughter. The three rush to the lifeboat, but the unsub regains control of Sullivan and threatens him with a gun. While the family is again captive, the lifeboat is released.
In reviewing security footage, Agent Garrett notices the unsub using a gesture after nearly being hit by a car. He determines that the gesture is Dutch in origin, and that it's unlikely he's an American.
They finally identify the unsub as Jerry Tidwell, who had killed his family when he was fifteen. At the time he was declared temporarily insane and hospitalized until he was 21.
Garcia and Monty find information to indicate Tidwell has inherited his uncle's fishing charter business. They quickly identify the boat and its location.
Tidwell throws Sullivan's son Nick over the side of the boat. The daughter Allison frees herself, and her mother Colleen tells her to run.
The teams converge on the boat. Tidwell grabs Allison and threatens to shoot her. JJ tells the girl to look at her, then tells her to drop. Allison drops, which gives Garrett an opening. He shoots Tidwell and kills him.
The teams rescue Nick as well, who had taken refuge in the lifeboat.