The body of a chief warrant officer is found in the bayou. His name was William Reed, and he worked in counter-intelligence. His previous job was at Gitmo where he worked as an interrogator.
The cause of death was drowning, but Wade and Lund determine that he wasn't drowned in the bayou - that's just where his body was dumped.
When they try to notify Reed's wife Marilyn, they find her missing. Upon searching her house, they realize the door had been jimmied and the house was trashed.
While searching the house, one of the Reeds' neighbours - Helaine Morgan - comes into the place. They question her but the only information she gives them is that she saw a dark colored car in the driveway the night before.
Outside the house, they find a blood mark on a bird bath, after which they theorize that Reed had come home, and surprised someone who then murdered him by driving his head into the concrete bird bath and then drowning him in it.
Their next visit is to Marilyn's brother - Oliver Huntington, who happens to be a wealthy man. He tells them his sister is at a hard-to-reach yoga retreat.
They later determine he's lying and when they confront him at his house, he attempts to flee in his car. The team boxes him him and he crashes the car and gives himself up.
The truth then comes out: his sister has been kidnapped. The kidnappers warned him not to speak to the police or they would kill her. Additionally, they demanded that he give them three million dollars within 24 hours.
The NCIS views a video that was texted to Huntington: in it, Marilyn is seated and holding a newspaper while she pleads for her brother to pay her ransom.
The team visits Huntingdon's lawyer, a man named Bernard Lanier, who tells them that Huntingdon has a trust fund from which a certain allotment of funds is given to him on specific dates.
Pride asks for help from FBI specialist Tobias Fornell, who does a linguistic profile based upon the words in the text message. He tells Pride that the kidnapper is well-educated, and well to-do, with a six-figure incoming. He also says that he was raised in the south, is articulate and patient.
The team goes back to the lawyer's office, thinking that he might be the kidnapper. When they approach the door to his office, they hear a gunshot. Barging in, they find the lawyer's body, dead from a self-inflicted gunshot wound. They notice that three million dollars has been transferred out of Huntington's account, but they can't find its destination.
Though the kidnapper appears to be dead, they have yet to find Marilyn.
Upon examining the video, the team notices that Marilyn Reed has hives, brought up probably by an allergic reaction. An analysis of the sounds in the video yields some background noise indicating the presence of a special type of sprinkler, one commonly found at greenhouses.
After mapping out all of Huntingdon's properties, they discover one that has a greenhouse - so they quickly go there. They find Marilyn locked up in a trailer.
Pride wonders why Lanier would shoot himself, knowing that he would transfer the money. He realizes that Lanier had a partner.
Pride realizes that Lanier's partner was the Reeds' next door neighbor Helaine Morgan. He confronts her on the waterfront, where she offers him a bribe.
He declines and arrests her instead.