The Bachelorette Party

In May 2012, four young women gather on Isle Blind, a barren, privately owned island in the Baltic Sea, for their annual overnight trip. Matilda Sperling, secretly nine weeks pregnant and uncertain about keeping the baby, confides in her friend Anna Wittenberg. When the group heads to the beach for a swim, Matilda finds Linnea Andersson lying on the shore with a fatal head wound. Before she can react, a black-clad figure drives a blade through Anna's throat. Matilda freezes, and the killer cuts her throat as well. The novel alternates between past and present timelines: Flashback chapters reveal what led to the massacre, while present-day chapters follow a bachelorette party held on the same island a decade later.

Ten years later, Tessa Nilsson, a disgraced true-crime podcaster and the novel's first-person narrator, prepares to attend her friend Anneliese's bachelorette party. Tessa is broke, facing a lawsuit, and isolated after a professional scandal destroyed her career. She planned to skip the event but changed her mind when she learned it would take place at Baltic Vinyasa, a new luxury yoga resort on Isle Blind. Tessa has spent years researching the disappearance of the four women, known as the "Nacka Four," and believes they were murdered on the island rather than drowning in a boating accident, as investigators concluded. She also discovered that the resort's owner, Irene, is Matilda's older sister.

Tessa's older sister, Lena, drives her to the harbor, where they meet the bridal party: Mikaela, the maid of honor and social media influencer; Natalie, a photographer Tessa has never met; and Caroline, a family therapist. At the resort, Irene collects everyone's phones as part of a digital detox policy and assures the group that a landline and a dinghy are available for emergencies. Tessa notes the extreme isolation.

During the first evening's dinner, Tessa is overwhelmed when the group asks about her career's collapse and flees to the beach. Caroline follows to check on her, and Tessa, loosened by wine, accidentally mentions the Nacka Four before asking Caroline to keep quiet. Earlier, Tessa met Adam, the resort's chef, who told her Matilda was murdered, sharply contradicting the official narrative, and warned her not to raise the subject with Irene.

Flashback chapters fill in Matilda's backstory. She was deeply ambivalent about her pregnancy, and her fiancé, Carl von Thurn, appeared loving but was controlling and manipulative, discouraging her from the trip. Carl had been secretly sleeping with several women, including Evelina Banér, one of Matilda's closest friends. When Evelina threatened to tell Matilda, Carl tracked the women to Isle Blind using a location-sharing app on their shared computer, confronted Evelina, and she fell and fatally struck her head while fleeing. Carl then killed the remaining three women, sank their bodies near the island, towed their boat far away, and scattered their phones to mislead investigators.

In the present, Tessa encounters Irene late at night and raises the cold case. Irene reveals she repeatedly told police Matilda would never have drunkenly taken a boat out, but they dismissed her. She gives Tessa cautious permission to investigate. The next morning, the dinghy is spotted drifting far from shore, and Caroline has vanished. A handwritten note claims she left to handle a patient emergency, but Tessa is skeptical: She was awake most of the night and heard no boat. Over the following day, her unease grows. She learns Adam grew up in the same affluent Stockholm suburb as the Nacka Four, and Mikaela reveals that Caroline lived in the same building as Matilda, a detail suggesting a hidden connection to the original case that deeply unsettles Tessa.

That night, while searching for Natalie along the shore, Tessa finds the dinghy has drifted back. Inside lies Caroline's body, her throat slit, rocks stuffed in her pockets, and holes punched in the hull. Tessa tells the group, but no one believes her until Mikaela and Natalie see the body themselves. When the three return to the bonfire, Lena, Anneliese, and Irene have vanished, the fire is stomped out, and the hotel is dark.

The novel also reveals Tessa's professional downfall. Desperate to reverse declining podcast numbers, she pursued an interview with Harald Sturesson, the father of a teenage murderer who had never spoken publicly. Tessa gained Harald's trust and recorded a deeply personal conversation, then edited his words into a sensational episode. Harald listened to the broadcast and cut his wrists. He survived, but the backlash destroyed Tessa's career and finances.

Tessa, Mikaela, and Natalie arm themselves and enter the dark hotel to reach the basement landline. Natalie is attacked in the corridor and Mikaela flees. Tessa reaches Irene's office and locks herself in, but the landline is dead, all phones are drained, and the internet is down. Irene knocks, claiming she escaped after Adam tied them up. Tessa lets her in, and Irene leads her upstairs to free the others. When Tessa enters the room, Lena, Anneliese, and Natalie sit bound and gagged, but Adam is also there, looking frightened. Irene steps in behind Tessa holding a shotgun. She is the real threat.

Irene forces Anneliese to acknowledge an admission from an earlier party game: She once provided a false alibi for an older man she was involved with. That man was Carl von Thurn. By lying when police questioned Carl, Anneliese helped the murders go unsolved. Adam reveals he was Linnea's boyfriend and joined Irene's plan believing they would only extract a confession to take to police. Irene also reveals she lured Carl to Isle Blind in 2020, forced a confession from him, and killed him, staging his death as a suicide. When Adam learns Irene murdered Caroline to silence her after she overheard their plans, he turns on Irene and demands they stop. Irene beats him to death with the rifle.

She fires the shotgun into Anneliese's chest, killing her. Lena, whose gag has come loose, throws herself onto Irene and screams at Tessa to run. On the patio, Mikaela, who returned instead of fleeing, cuts Tessa's zip ties with broken glass. As they try to escape, Irene fires her second and final shell into Mikaela's back. Tessa runs into the trees. Irene, out of ammunition, pursues with the rifle as a club. She catches Tessa on the beach and forces her into the shallow water, attempting to drown her. Mikaela, still alive, appears and kicks Irene unconscious.

Tessa finds Lena upstairs, badly wounded but alive, clutching the dead phone. Lena whispers that a charger is in Irene's room. In the basement, Tessa discovers a rosewood box under Irene's bed carved with Matilda's name, filled with polished bone fragments Irene collected from the beach, believing them to be her sister's remains. Beside it is a phone charger. Tessa plugs in the phone and dials emergency services.

Six months later, Tessa lives in a small apartment, attending therapy and slowly rebuilding. Lena remains hospitalized but refuses to let Tessa blame herself. Mikaela survived and is thriving. Natalie, who experienced two small strokes from the attack, has recovered and meets Tessa weekly for photography outings, the beginning of a tentative romance. Tessa deletes a predatory email from her former producer proposing a podcast about the killings. She cannot attend Anneliese's funeral because her body is still too broken, and the guilt will never fully leave. But walking along the Stockholm waterfront with Natalie's hand in hers, she allows herself to believe that good enough might be enough.