DEEP WATER*CUT TO THE CHASE*
NOTE: This spoiler was submitted by Jeremy
The film starts with Vic Van Allen (Ben Affleck) riding his bike home after a ride through the woods. He takes his pants off as he gets to the door, then looks up to find his wife Melinda (Ana De Armas) looking at him.
The couple has a daughter, Trixie (Grace Jenkins), and live in Louisiana. They go to a party where they meet their friends, including Vic’s buddies Grant (Lil Rel Howery) and Jonas (Dash Mihok). Melinda goes off with a musician, Joel Dash (Brendan C. Miller), and Vic watches them kissing outside. He talks to another friend, Mary (Devyn Tyler), who expresses concerns to Vic over Melinda being with another man, but Vic says it doesn’t concern him. He joins Melinda as she drunkenly plays a song on the piano.
Joel approaches Vic to chat. When they are alone in the kitchen, Vic casually mentions another “friend” that Melinda had named Martin McRae, who went missing a month earlier. Vic tells Joel that he killed him with a hammer, which Joel takes as a threat towards himself.
The “joke” about Vic killing Martin goes around the neighborhood, though he claims he never meant to threaten Joel. What his friends and neighbors do not know is that Vic and Melinda have a personal arrangement – they know there is no love in their marriage, and so Vic lets Melinda sleep with whoever she wants so that they don’t get divorced, but only as long as she doesn’t leave him and Trixie. Joel is planning to move over the weekend, so Melinda invites him over for dinner to sort things out with Vic. The dinner goes awkwardly, and after Vic puts Trixie to bed, she tells Vic she doesn’t like Joel.
The Van Allens go to a party where they meet a couple, Don and Kelly Wilson (Tracy Letts and Kristen Connolly). Don is an author, and Vic tells him he works for a magazine publication company. Don heard about Vic supposedly killing Martin and brings it up. Vic later dances with Kelly while Melinda watches. She brings it up on the ride home, and it is enough to get them running to have sex.
While at a soccer game for Trixie, Vic gets a phone call about a payment Melinda made to a piano teacher named Charlie De Lisle (Jacob Elordi). Vic follows Charlie and sits in at the lounge where he plays. Seeing that he is a handsome young man, Vic figures that Melinda is seeing Charlie behind his back. Later that night, Martin’s body is reported to have been found with a gunshot to the head.
Vic and Melinda go to a pool party at Jonas’s house with their friends, where Charlie is in attendance. Melinda introduces Charlie to Vic as her piano teacher, Charlie being unaware of previously seeing Vic at his lounge. Vic watches Melinda and Charlie getting close in the pool. Later on, it begins to rain, forcing everyone inside. Vic comes in afterward, and Melinda looks outside to see Charlie floating facedown in the pool. The guys pull him out and attempt to resuscitate him, but Don accidentally drops Charlie’s body, bumping his head against the edge of the pool. However, they determine that he was already dead when they found him. Police come to question the guests, with Melinda outright accusing Vic of drowning Charlie, but Vic denies it, and he isn’t brought in for further questioning.
Melinda works with Don to hire a private investigator, David Ricigliani (Joel R Martinez), to tail Vic. He catches onto them quickly and goes to Don’s house to confront him in front of Kelly and their daughter.
Vic observes Melinda getting back with her college boyfriend, Tony Cameron (Finn Wittrock). Tony goes to the Van Allen house where Vic is friendly toward him. He later runs into Tony on the street and tells him Melinda wants to show him something. He drives Tony out to the woods where he gets him alone and then throws a rock at his head. Tony stumbles down a cliff and smashes his head onto a rock, killing him. He then attempts to hide Tony’s body in the water.
Vic later takes Melinda and Trixie out for a picnic in the woods. He becomes worried when Trixie almost comes across Tony’s body. On the drive back, Melinda mentions having left her scarf behind.
The next day, Vic goes back to try and sink Tony’s body further in, but Don comes around the area. Before Vic can get rid of Don, he spots Tony’s arm floating. Don begins to try and drive away, but Vic chases after him on his bike. Vic takes a shortcut and falls off his bike, just before Don drives and swerves hard to avoid hitting him, causing Don to drive down a large hill and crash his car below where he dies.
Vic returns home to Melinda, who tells him she found Tony’s stuff, but she won’t say anything. She is later seen burning Tony’s ID.
Vic and Melinda Van Allen are a married couple who have an arrangement where Melinda can be with any other man she wants so they can avoid divorcing, but only if Melinda doesn't leave Vic and their daughter Trixie. However, Vic becomes dangerously jealous.
Vic kills one of Melinda's lovers, Charlie, by drowning him in a pool during a party, and Vic manages to avoid incarceration. He later lures her old boyfriend Tony to the woods after she starts seeing him again, and he causes Tony to fall down a hill and hit his head on a rock. While trying to hide Tony's body, he is found by a neighbor named Don who had already been suspicious of Vic. Don ends up accidentally driving his car off a cliff to his death.
Melinda finds Tony's ID but opts to keep Vic's crime a secret.