On a steamy July evening, Pam Montgomery hosts a backyard dinner for four couples who have been close friends for years: Pam and her husband Hank, the casino's director of operations; Marlene and Dave Brand; Nancy and Larry Clooney, a bank manager; and Shalisa and Andre Murphy, who runs a courier service. The marriages are strained. Five years earlier, Hank convinced the other men to invest in a deal that collapsed, wiping out all four couples' retirement savings. When Andre publicly tells Shalisa she doesn't "need" a slice of her own cheesecake, Pam senses something shift. Two days later, Dave is found dead under the heavy, manual garage door Marlene had long begged him to replace.
Marlene reveals that Dave had insured himself heavily, including a $1 million life insurance policy that erases her debts and funds a condo in Boca Raton. She also discovered that Hank, Larry, and Andre carry identical policies. With Marlene gone to Florida, the remaining wives voice what they have been burying. Shalisa hides food from Andre because he polices her diet. Nancy reveals Larry refuses to meet their son Paul's partner, Estuardo, a lawyer, effectively rejecting his own child. Pam admits she wouldn't miss Hank. Nancy asks plainly: Why don't they kill their husbands, collect the insurance, and start over? Shalisa agrees. Pam resists until Hank eats her leftover pad thai, her favorite food, and admits he wasn't even hungry. She texts her friends: She is in.
The novel shifts to Hank's perspective, revealing he believes Dave was murdered. At the scene, he found a $1,000 casino chip on Dave's chest and an ax in Dave's hand, which he read as signs of a professional hit. He staged the scene and called 911. In flashback, the men's secret emerges: Four years earlier, Dave discovered a glitch in the casino's slot machines that generated fraudulent payout vouchers. The four men built a theft operation: Dave created vouchers, Hank relayed them to Andre's courier shop, Andre's runners redeemed them, and Larry wired the proceeds to offshore accounts. By Dave's death, they had amassed $9.3 million, driven by guilt over the failed investment and hope of restoring their marriages. Andre insisted each man carry a $1 million life insurance policy for their wives.
When Indo-USA Gaming Inc., a company with ties to organized crime, took over the casino, the men grew nervous. Padma Singh, the young new president of operations, noticed the slot machines overpaid by roughly $2.5 million per year, a finding Hank believes triggered Dave's murder. Hank hires his barber, Hector Chavez, a Salvadoran immigrant whose scarred past suggests gang involvement, to protect them. Hector is married to Brenda Palumbo-Chavez, a former private investigator, and the two operate as a team. When the wives hire Hector for $150,000 to kill their husbands, he realizes the wives are the threat the husbands feared. He accepts both jobs. Brenda calls it a "double dip": Both sides are paying, but only one job needs doing.
Events accelerate when Hank overhears Padma on a Zoom call discussing three prospective grooms a matchmaker is sending from Mumbai. He misinterprets the conversation as orders dispatching hitmen. Panicked, Hank convinces Larry and Andre to fake their deaths. They negotiate with Hector to blow up their boat and smuggle them to El Salvador, and they cancel their life insurance policies to reduce scrutiny, unaware their wives depend on those payouts.
On Friday evening, the group takes the boat out to scatter Dave's ashes. The outing stirs deep emotion in Pam, and when her daughter Claire calls to announce she is pregnant and moving home, Pam declares they cannot go through with the murders. Nancy and Shalisa reluctantly agree. Minutes later, police arrive with news of a catastrophic boat explosion. No bodies are recovered, but officials issue Presumptive Death Waivers, allowing the men to be declared dead.
The wives grieve in confusion. Clues emerge in stages: The insurance policies were canceled the day of the explosion; Andre left a laminated apology card in a juniper stump; Larry left a letter accepting Paul's relationship with Estuardo; and in Hank's sent folder, Pam finds a link to a show about a man who faked his death on the water. That night, Nancy watches Larry's emails being opened and marked unread by someone accessing his account remotely. The husbands are alive.
The casino sends Farid Nadir, a forensic accountant nicknamed "The Fiscal Falcon," along with four men who appear to be enforcers. Farid tells Pam the wives must return the stolen $10 million or face the consequences. The wives confront Hector, who confirms the men are hiding at his mother's house in El Salvador, and threaten to expose him unless he persuades the husbands to return the money. In San Salvador, Hector delivers the ultimatum and reveals that the wives hired him to kill them. The men are stunned. Andre shares a long-held secret: He was diagnosed with testicular cancer shortly after marrying Shalisa, and treatment left him unable to have children. Rather than burden her, he lied and said he didn't want kids. After anguished debate, all three agree to surrender the funds, though Larry holds back about $300,000 by claiming they stole only $9 million.
The handoff proceeds through a Virtual Safety Deposit Box, a secure online vault for transferring the bank draft. Farid takes Pam's rescue dog, Elmer, as collateral until the transfer clears at midnight. When Hector enters the casino basement to retrieve Elmer, Farid points a gun at the dog. Hector shoots Farid, then uses Farid's fingerprint and face to unlock the laptop, cancels the transfer, and redirects the $9 million to an anonymous account he and Brenda control. Padma concludes Farid stole the money and fled, a narrative that benefits her by discrediting her mother's agent.
Six months later, Hector and Brenda have built an animal rescue and resort on the Salvadoran coast. Hank tends bar, Andre runs the front desk, and Larry manages finances. Each wife received an anonymous $100,000 settlement, implied to come from the funds Larry held back. Brenda arranges a trip to bring the four women and Elmer to the resort. Pam sees Hank emerge from behind the bar, and after a cautious exchange, she runs into his arms. Nancy and Larry reunite at the pool. Shalisa, who had briefly separated from Andre, tells her friends they belong together. Paul and Estuardo's wedding is held at the resort, with Larry and Nancy walking Paul down the aisle, Larry pulling his son into a hug.
A postscript reveals Dave's death was a genuine accident. That morning, Dave rushed into his cluttered garage to grab an ax Andre had asked to borrow and a $1,000 casino chip he had found on the floor outside the casino bank weeks earlier, after Padma slipped in a coffee puddle and the chip fell from her tray. Dave tripped on a snow shovel, struck his head on a steel Christmas tree stand, and fell unconscious as the garage door crashed onto his skull. The chip landed on his chest; the ax stayed in his hand. Hank's misreading of this scene as a professional hit set the entire chain of events in motion.