Heather attends a therapy session with a psychologist named Inna. Heather explains that her childhood trauma and a lack of physical proof make her doubt her own perceptions of Stephen’s abuse. Inna asks what Heather believes in her heart.

The narrative shifts forward to the wedding, where a group of guests, including Fiona, moves to a nearby pub and gossip about the strange events. After hearing a group of women praising Stephen, Fiona speaks up and states that Stephen beginning a new relationship while still married to Pamela is in keeping with his character.

At the wedding rehearsal dinner, Tully notices that Heather looks calm. Tully reflects on recent changes: her family has moved, Miles is in therapy, and she has a new job. She fights the daily urge to shoplift while awaiting her court date. Stephen proposes bringing Pamela to the wedding. Tully sees Rachel’s unease but reluctantly agrees.

Rachel attends the rehearsal dinner with Darcy and feels steadier since starting therapy. Stephen greets Darcy warmly, and Rachel struggles to reconcile his kindness with her fears. Stephen apologizes for the recent strain in their relationship and pleads for Rachel to acknowledge that he would never hurt Pamela. Rachel cannot say the words.

Heather feels happy at the rehearsal dinner. Stephen gives an emotional speech, and she feels safe with him. About a week earlier, Heather finally revealed to Stephen that her father is in prison after murdering her mother. Stephen already knew this information, but he expressed his happiness that she trusted him. In turn, he confided that he was married to Fiona Arthur before his marriage to Pamela. This newfound trust makes Heather feel confident and safe as she prepares for her wedding.

On the wedding day, Rachel and Tully bring a confused Pamela to the chapel. When Stephen appears at the altar, Pamela walks toward him, and he gently guides her back to her seat. Heather walks herself down the aisle. As the ceremony begins, Pamela shrugs off Rachel’s hand and walks toward the altar.

When Pamela reaches the altar, Heather offers her the bouquet to defuse the moment. Pamela accepts and returns to her seat. The ceremony resumes. As Stephen produces the rings, Pamela grows restless. She rises a second time and walks with purpose toward the altar.

As the ceremony concludes, Pamela picks up a heavy candlestick. The wedding party moves into the sacristy to sign the register. Pamela begins swinging the candlestick erratically, which becomes dangerous as Tully’s young sons leap around the room. 

Stephen intervenes, locking Pamela in a chokehold. Tully and Rachel both observe with shock that Stephen handles Pamela far more roughly than he needs to and seems to be enjoying grabbing hold of her. Tully watches as Rachel (who had taken the candlestick from Pamela) strikes her father in the head.

Stephen collapses, and blood spreads across the floor. Tully, Heather, and Pamela stand shocked. Rachel feels confident that Stephen’s behavior confirmed her suspicions and that he abused Pamela. The celebrant runs from the room to call for a doctor.

Several guests rush in to help while Sonny calls an ambulance. When Sonny asks what happened, Tully lies that Pamela hit Stephen by accident. Rachel starts to confess, but Heather quiets her and supports the cover story. Sonny repeats Tully’s version to the doctors.

Hours later, Heather waits in a hospital hallway in her bloodied wedding dress. A doctor confirms Stephen’s death. Heather returns home alone and in shock.

At the pub, Fiona Arthur waits with other guests. A man announces that Stephen was accidentally injured and did not survive. Guests toast Stephen as a good man. Fiona lifts her glass but mutters her own, different verdict.

Tully, Rachel, and Heather gather after Stephen’s funeral. Heather toasts to bad fathers and reveals that her father is in prison for murdering her mother. The three women acknowledge their secrets and decide to stop hiding the truth from each other.

After Stephen’s death, Rachel, Tully, and Heather all give statements attesting that Pamela accidentally killed Stephen while swinging the candlestick randomly. Pamela’s Alzheimer’s disease makes it unlikely she will face criminal charges. Rachel and Darcy begin to visit Pamela regularly. To stir Pamela’s memory, Rachel brings old photos. When Pamela sees an early picture of herself with Stephen, she lifts the frame and kisses his image.

Two months later, a court sentences Tully to 100 hours of community service for theft. She finds satisfaction in the work and befriends another participant. Her son Miles improves, and her family’s smaller life feels manageable. She admits she misses some good parts of her father, accepting that he was not entirely evil.

On Christmas Day, Heather hosts the family. Pamela died of pneumonia a month earlier. Tully and Rachel wish that they had confronted Stephen and heard him admit the truth. Rachel also expresses that she sometimes has nagging doubts about whether Stephen was abusive. Heather tells them to trust what they saw at the wedding, saying Pamela’s hidden money proves she felt confident in her instincts. The sisters agree to move forward.

The epilogue takes place three years before the main plot, at which time Pamela is just beginning to experience confusion and trouble with her memory, signs of her incipient cognitive decline. Pamela has received the water bottle stuffed with money from her own mother, who gave it to Pamela just before passing away. Pamela wonders what to do with the money. She has recently begun having suspicions about whether Stephen might be physically harming her; while Stephen has always denied this, Pamela has noticed that she experiences strangely unexplained injuries. 

Pamela recalls that, years earlier, Fiona made a cryptic statement, warning her about Stephen. She decides to reach out to Fiona to ask if Stephen ever harmed her. Not wanting to forget this intention, Pamela writes down Fiona’s name. She also writes down Tully’s name because she plans to ask for her daughter’s help if she receives confirmation that Stephen is abusing her. 

Startled by the sound of Stephen approaching, Pamela places the notes with the names and the money back in the water bottle and tucks it away, intending to come back and carry out her plan. The narrative implies that, due to her failing memory, she never did so.