The first book in Ann Cleeves's Shetland Series opens on New Year's Day on the remote Shetland Islands of Scotland. Magnus Tait, an elderly recluse living at Hillhead in the rural Ravenswick area, waits for visitors who have not come in eight years. Two drunk teenage girls arrive on a dare: Sally Henry, whose mother Margaret is the village schoolteacher, and Catherine Ross, an English girl whose family moved to Shetland after her mother died of cancer. Magnus is fascinated by both, especially Catherine, whose boldness captivates him. The girls drink his whisky, eat his cake, and leave laughing.
Sally recalls earlier events from Hogmanay, Scotland's New Year's Eve celebration. At the festivities in Lerwick, Shetland's capital, she flirts with Robert Isbister, a wealthy young man from a prominent local family. They kiss in the back of a car heading toward Ravenswick, with Catherine in the front seat beside an unidentified driver. After being dropped off, Catherine spots Magnus's light and dares Sally to knock on his door.
In the following days, Catherine encounters Magnus on a bus and walks him home. He invites her in for tea, and she accepts. He compares her privately to his caged raven: his treasure. On January 5, Fran Hunter, an English artist and single mother, pulls her five-year-old daughter Cassie to the Ravenswick school on a sledge. Walking home, Fran notices ravens in a snow-covered field. She realizes the red she sees is a scarf wound tight around a young woman's neck. It is Catherine Ross. Alex Henry, the schoolteacher's husband, sees Fran in distress and calls the police.
Magnus watches from his window. He recalls being interrogated years earlier about the disappearance of a girl named Catriona Bruce, a violent questioning that left him with broken teeth. His mother's instruction echoes: "Tell them nothing." He knows the police will come again.
Inspector Jimmy Perez, a Shetlander of Spanish descent from Fair Isle, arrives to investigate. He interviews Fran, who describes Catherine's father Euan Ross as a widowed former headmaster now teaching at Anderson High School. She tells Perez she last saw Catherine walking with Magnus. At Hillhead, Magnus blurts out Catherine's name before Perez identifies the victim, then admits she visited for tea the day before. Perez asks about Catriona Bruce, who also visited Magnus before vanishing eight years ago. Magnus retreats into silence.
DI Roy Taylor arrives from Inverness as senior investigating officer. Perez argues against assuming Magnus is guilty, noting that Catriona's body was hidden while Catherine's was displayed, and Catriona was a child while Catherine was a streetwise young woman. Taylor agrees to keep Magnus under surveillance rather than arresting him.
The investigation broadens. Sally tells Perez that Magnus fixated on Catherine. David Scott, Catherine's English teacher, confesses to kissing her; she pushed him away in disgust. Robert claims he barely knew Catherine. Post-mortem results confirm Catherine was strangled with her scarf between 6 p.m. and midnight on January 4, with no sign of struggle. No footprints from Catherine appear at the crime scene, meaning she walked there before it snowed and her tracks were covered. Perez argues she went willingly with someone she trusted.
At night, Magnus slips past the police and climbs to a peat bank near the Gillie Burn, the site where he buried Catriona eight years ago. Perez visits Duncan Hunter, Fran's ex-husband, at his estate, the Haa. Duncan describes Catherine as elated at a party he hosted the night before her death but denies a sexual relationship with her. Celia Isbister, Robert's mother and Duncan's longtime lover, left Duncan that night after receiving a text message.
Fran discovers a second body on the hill above Ravenswick, exposed by a landslip. The peat has perfectly preserved a small girl in a yellow cotton dress: Catriona Bruce, dead for eight years. Magnus sees the police activity, dresses in his funeral suit, and lays out hair ribbons he took from the dead girl's body. At the station, he admits taking the ribbons but insists Catriona was already dead. He denies killing Catherine. The procurator fiscal, a Scottish legal officer who decides whether to prosecute, charges Magnus with Catriona's murder.
Catriona's brother Brian Bruce tells Fran that on the day she disappeared, Catriona ran up the hill with flowers for Magnus's mother Mary Tait. Meanwhile, Euan becomes convinced that Catherine's missing film provides a motive for her murder. Her camcorder and a disk have been stolen, and files have been wiped from her computer. Fran helps Euan search Catherine's belongings and finds a notebook titled "Fire and Ice," after the Robert Frost poem, containing documentary notes about Shetland. A receipt dated January 4 proves Catherine was alive when she left Magnus's house. The initials "RI," likely Robert Isbister, appear next to a January 3 date.
Jonathan Gale, the student who drove the car on New Year's Eve, corrects an earlier assumption: Robert was kissing Sally that night, not Catherine. Duncan tells Perez that Robert and Catherine disappeared together at the Haa party for about an hour; Catherine returned flushed and elated while Robert never came back. Celia reveals that Catherine was filming the party and that watching herself on camera prompted her to leave Duncan.
Sally begins seeing Robert in secret. They sleep together, and Sally starts babysitting Cassie as cover for their meetings. On Up Helly Aa night, Shetland's annual torchlit Viking festival, Fran takes Cassie to watch the procession in Lerwick. A momentary distraction, and Cassie vanishes from the crowd. Perez and Taylor treat the disappearance with urgency.
Perez visits Magnus in his cell and asks for the truth about Catriona, arguing it might help find Cassie. Magnus overcomes his mother's lifelong command and reveals what happened: Catriona ran to Hillhead with flowers and found toys belonging to Magnus's dead sister Agnes. Magnus's mother Mary appeared, furious. When Catriona refused to return a doll, Mary grabbed her knitting scissors and stabbed the girl in the chest, killing her. Under Mary's direction, Magnus buried the child and never spoke of it.
Taylor searches the schoolhouse and finds Catherine's keys and the stolen film evidence in Sally's bedroom. Perez returns to the Haa, where Sally and Robert are on the beach. He finds Cassie bound and gagged in Robert's van, alive but terrified, and carries her inside.
On the beach, Perez confronts Sally. Robert reveals that Catherine filmed him hitting her; Catherine had deliberately provoked the violence and captured it on camera. Sally confesses: Catherine showed her the footage and mocked Sally's feelings for Robert. The taunting echoed years of bullying, and Sally snapped, pulling Catherine's scarf tight until she was silent. Afterward, Sally took the camcorder, stole the disk from Catherine's room, deleted the files, and walked home undetected. She kidnapped Cassie because the child had seen Sally with Catherine through a window the night of the murder.
Perez visits Fran and explains the full story: Catherine was a natural director who manipulated people for her film, provoking reactions and capturing them on camera. When she taunted Sally with Robert's violence and mocked Sally's feelings, it triggered years of pain. Fran kisses Perez on the cheek. He returns home and calls his mother about a vacant croft, a small farmholding, on Fair Isle. His decision is left unresolved as the novel closes.