Part of Ann Cleeves's Two Rivers series, this novel follows Detective Inspector Matthew Venn and his team as they investigate connected murders in the rural communities of North Devon, England.
The story opens on a Friday evening at a party hosted by Cynthia Prior, a local magistrate, in the coastal town of Barnstaple. Detective Sergeant Jen Rafferty, a single mother and member of Venn's team, meets Nigel Yeo, a former doctor who heads North Devon Patients Together (NDPT), an organization that monitors the local NHS health trust. Nigel hints that he wants to discuss something professional but says the party is not the right place. He leaves after asking for her work contact details.
The next morning, Matthew calls Jen to a crime scene at Westacombe Farm, an artists' commune near the village of Instow where converted farm buildings serve as studios and flats. In a glass-blowing studio, Nigel lies dead, a long shard of green glass piercing his neck. His daughter, Eve Yeo, a glass blower who lives and works at the farm, identifies the murder weapon as a piece from one of her own handmade vases. She had expected Nigel that morning to assist her, as he regularly did, but has no idea why he came during the night. Eve tells Jen that something at work had recently been troubling her father, though he would not discuss it.
Matthew interviews Francis Ley, the reclusive owner of Westacombe, a wealthy economist motivated by guilt over his fortune. Ley reveals that a young friend, Alexander Mackenzie, known as Mack, died by suicide the previous autumn by jumping from a cliff at Seal Point. Mack had been hospitalized for severe depression and paranoia but was discharged after one night, and community mental health support never materialized. Ley asked Nigel to investigate whether the health trust's negligence contributed to Mack's death on behalf of the Mackenzie family: George and Martha, who run a bar called the Sandpiper in Instow, and their daughter Janey, an Oxford graduate working in the family business.
Another Westacombe resident, Wesley Curnow, a musician and driftwood artist, reports that a car nearly hit him in the farm's lane around 1 a.m. as he returned from the party. Matthew searches Nigel's home and finds key evidence: A diary entry for the day of his death lists a morning hospital meeting with Roger Prior, the CEO of the health trust and Cynthia's husband, along with a barely legible scribbled number. In the bedroom, two dressing gowns and two toothbrushes suggest a secret relationship. Matthew visits Lauren Miller, Nigel's colleague at NDPT, who confirms they were lovers and had kept the relationship private partly to avoid upsetting Eve, still mourning her mother.
On Sunday, Matthew and his husband, Jonathan Church, who manages the Woodyard arts centre in Barnstaple, host a birthday lunch for Matthew's estranged mother, Dorothy Venn, a tentative step toward reconciliation. The celebration is cut short by a second murder. Eve receives a text, apparently from Wesley's phone, asking her to meet him at his storage shed at the Woodyard. She arrives to find Wesley dead, a shard of blue glass in his neck. Eve identifies the glass as coming from a vase she made for Ley, displayed in his living room the day before. Matthew determines the text was sent by the killer from Wesley's missing phone to torment Eve.
The team pursues multiple leads. Jen discovers that Roger Prior was forced to resign from a previous post after a teenager named Luke Wallace died by suicide in a hospital under his authority. Luke's mother tells Jen her son used an online forum called Peace at Last, which encouraged people considering suicide. Mack's suicide note used the same phrase, and Nigel had contacted Luke's mother in the week before his own death. Meanwhile, Matthew and Detective Constable Ross May meet hospital officials who claim Nigel left their Friday meeting satisfied. Afterward, psychiatrist Ratna Joshi privately contradicts this account: She saw Nigel later that Friday, furious, saying he would not be silenced and the truth had to be told.
Ross's friend Steve Barton, a digital forensics specialist, analyzes Mack's laptop and confirms Mack belonged to the Peace at Last chatroom and its inner circle, the Suicide Club, where members actively encouraged each other toward death. Among the members, Ross recognizes Francis Ley. Days later, Ley disappears from Westacombe. Jonathan, who has volunteered to help search the grounds, finds Ley's body in a gorse thicket on the common. A suicide note addressed to Matthew says Ley's generosity no longer eases his guilt and that he is glad to find "peace at last."
Jen suspects John Grieve, the husband of Eve's close friend Sarah Grieve and a Westacombe resident who spends hours secretly on his computer. His secret, however, proves to be an online gambling addiction. Matthew learns from Ley's solicitor that Westacombe is left to Sarah and her heirs, with the studios going to Eve and Wesley.
Steve Barton identifies the Suicide Club's moderator, known online as "the Crow," as Roger Prior, who had been pushing vulnerable members toward death. Separately, Eve spends a sleepless night piecing together clues, including a sound she heard before finding her father's body. She contacts George Mackenzie rather than the police, and her questions about Janey's whereabouts tip off the family. When Eve arrives at the Woodyard for supper with Jonathan, George and Janey, already there for a touring theatre production, abduct her.
Jen's theory crystallizes: The killer is Janey Mackenzie. Matthew and Jen race to the Mackenzies' chalet at Seal Bay and up the clifftop path, where they find George holding a shard of yellow glass to Eve's neck. Matthew speaks calmly, appealing to George's love for his family. Jen seizes a moment to grab George from behind and disarm him. The glass flies over the cliff, and Eve is safe.
Janey confesses. She pushed Mack from the cliff after weeks of exhaustion from his relentless demands, then staged his death as a suicide. When Nigel discovers guilt-processing writings Janey had composed in the family chalet, using the door code noted as the mysterious number in his diary, he confronts Janey at the party and demands she meet him at Westacombe. She kills him with Eve's glass. She kills Wesley because he phones her the next day suggesting he recognizes her face when she nearly runs him down while speeding away in Nigel's car. She stabs him with blue glass stolen from Ley's house and sends the text from Wesley's phone to lure Eve to the scene. George learns the truth only when Eve calls him; unable to lose another child, he is swept along by Janey's plan.
The case resolves. Ross learns his wife Mel's recent distance stemmed from a breast cancer scare, which proves benign. Jen reconciles with Cynthia, who tells Roger to leave after learning about his role in the Suicide Club. Matthew arranges for Lauren to care for Eve. Driving home across Braunton Great Marsh, he sees a solitary grey heron standing motionless in the water and feels the tension drain away. At home, a thank-you card from Dorothy for the birthday lunch signals that their reconciliation has taken hold.