The first installment in Camilla Läckberg's Fjällbacka series is set in a small Swedish fishing village, where gossip spreads fast and secrets run deep. The novel opens with a brief prologue: An unnamed man sits beside a bathtub where a woman lies dead, ice forming around her body and blood congealed on her wrists. He thinks of her as an ice princess and leaves without looking back.
Erica Falck, a 35-year-old biographer, is staying at her late parents' house in Fjällbacka, sorting through their belongings. During a winter walk she encounters Eilert Berg, an elderly retired fisherman who has just discovered the body of Alexandra Wijkner in a nearby house, her wrists slashed. Erica enters and recognizes Alex as her childhood best friend. The two were inseparable until Alex's family abruptly moved to Göteborg over 25 years earlier. That evening, Erica's younger sister Anna reveals that her controlling husband, Lucas Maxwell, wants to sell the family house.
Alex's parents, Birgit and Karl-Erik Carlgren, insist their daughter did not kill herself, citing Alex's lifelong phobia of blood. They ask Erica to write a memorial article, and she privately begins conceiving a book about Alex's life and death. The novel introduces Anders Nilsson, a painter with a severe alcohol addiction who produces abstract canvases of remarkable talent, and a childhood classmate of Alex's. He rages about Alex, furious she was going to ruin everything. His mother, Vera, cares for him devotedly, tormented by guilt over a choice she made 25 years earlier.
Erica interviews Alex's husband, Henrik Wijkner, at their villa on the island of Särö. He describes Alex as beautiful but emotionally inaccessible. She then visits the art gallery Alex co-owned with her friend Francine Bijoux Sandberg. Francine reveals that Alex had been secretly meeting a man in Fjällbacka and was three months pregnant. The baby was not Henrik's. Francine insists Alex was overjoyed about the pregnancy and could not have taken her own life.
The case turns sharply when forensic pathologist Tord Pedersen calls Superintendent Bertil Mellberg at Tanumshede police station with autopsy results confirming murder. Both wrist incisions were identically deep and straight, impossible in a self-inflicted wound, and toxicology showed Alex was unconscious from a sedative. She was three months pregnant and had previously given birth. Detective Patrik Hedström, Erica's childhood friend who has long harbored feelings for her, reconnects with Erica and begins sharing case details.
One evening Erica secretly enters Alex's house using a spare key. In the bedroom wardrobe she discovers a large unsigned nude painting of Alex. While searching, she hears an intruder enter and hides. After the person leaves, she grabs a piece of paper from Alex's drawer and flees. The paper is an old newspaper article about the 1977 disappearance of Nils Lorentz, son of the wealthy Lorentz family, who own the town's cannery.
At Alex's funeral, Erica observes Julia Carlgren, Alex's much younger sister, who flinches at Birgit's touch and refuses to place a flower on the casket. The reclusive Nelly Lorentz, the Lorentz family's elderly matriarch, makes a startling appearance, whispering with Julia while Birgit watches in horror. Erica learns from Francine that the painting's style matches Anders Nilsson's work. During a later visit to Nelly's villa, Erica discovers a copy of Nelly's will naming Julia as the primary heir to the Lorentz fortune and meets Jan Lorentz, Nelly's adopted son, who runs the cannery. Patrik, researching Jan's background, discovers his birth name was Jan Norin and that his parents died in a suspected arson fire in 1975.
Anders is arrested after a neighbor testifies she saw him at Alex's house the evening of the murder but is released when another neighbor provides a time-based alibi. Patrik and Erica reconstruct the crime scene: Alex prepared a dinner for two, but her guest never arrived. One wine glass was wiped clean of fingerprints, and the sedative was likely dissolved in her cider. Patrik notices a small leather patch on Alex's nightstand inscribed "T.T.M. 1976."
After spending the night together, Patrik realizes the next morning that Anders's alibi rests on a TV show that was preempted that evening, collapsing his defense. Before Patrik can act, Anders is found hanged in his apartment with no furniture nearby, making suicide appear impossible. Patrik discovers a notepad with faint impressions from a missing page and a leather patch identical to the one on Alex's nightstand. Meanwhile, Erica redials the last number on Alex's phone and reaches Dan Karlsson, her oldest friend. She realizes the intruder had taken a poetry book that would identify Dan as Alex's lover. Dan confesses to the affair, admits he was supposed to meet Alex the Friday she died but stayed home out of cowardice, and is devastated to learn she was pregnant with his child.
Anna flees to Fjällbacka with her children after Lucas attacks their daughter Emma, breaking her arm. The sisters confront years of unspoken truths about Lucas's abuse. Patrik visits the social worker who handled young Jan Norin's case, learning that Jan experienced severe neglect and probable sexual abuse and displayed disturbing behavior after his parents' fire.
Station secretary Annika Jansson discovers that the Carlgren family disappeared for an entire year between leaving Fjällbacka in 1977 and Alex's enrollment at a Swiss boarding school in 1978. Patrik confronts the Carlgrens, and Karl-Erik finally reveals that Alex was sexually assaulted by Nils Lorentz, her substitute teacher, beginning when she was about nine. By age 10 she was pregnant. Instead of reporting Nils, the family struck a deal with Nelly Lorentz for silence in exchange for financial support. The baby was kept and raised as Alex's younger sister. Julia appears and reveals the truth: She is not Alex's sister but her daughter, born from the assault. Karl-Erik collapses from a heart attack but survives.
The notepad from Anders's apartment yields a suicide note, confirming he took his own life. At Anders's funeral, Patrik walks Vera home and implies Alex's unborn child may have been Anders's grandchild. Vera confesses everything. She found Anders hanging and staged the scene as murder by removing the chair and his note to spare him the stigma of suicide. She then confesses to killing Alex. She went to the house that Friday to persuade Alex not to expose the secrets about Nils. When Alex refused, Vera crumbled sleeping pills into Alex's cider, waited for her to lose consciousness, and slashed her wrists to simulate suicide. Patrik had grown suspicious after Eilert confirmed the house's furnace was working normally, contradicting Vera's earlier claim that she sat freezing in the cold house. Patrik suspects her deeper motive was shame over 25 years of silence about the abuse.
In a final confrontation, Patrik presents Jan with his theory: Nils abused not only Alex and Anders but also Jan, and the three children, bonded as "The Three Musketeers" (the meaning of "T.T.M." on the leather patches), killed Nils together. Jan confirms it. The children lured Nils onto the frozen sea, pushed him through a hole in the ice, and watched him drown. Jan also implies he set the fire that killed his birth parents. He boasts that the statute of limitations protects him and gloats about inheriting the Lorentz fortune, unaware that Nelly's will leaves the estate to Julia. The case of Nils Lorentz remains officially unsolved.
In the closing pages, Erica tells Patrik her publisher wants her true-crime book on Alex. She reflects on her deepening relationship with Patrik and her reconciliation with Anna. In a final vignette, Eilert Berg sits on a balcony in Spain, having secretly fled his domineering wife, enjoying the sun and contemplating a new beginning.