A fire breaks out in an old school on Valo Island in the middle of the night. When Patrik Hedström goes to investigate, he meets Ebba Stark, who, together with her husband, recently returned to the island to try and get over the death of their only child. Patrik's wife, the crime writer Erika Falck, believes the attack on the school is directly linked to Ebba's tragic past. In 1974, her entire family disappeared while vacationing in Halo. One-year-old Ebba was adopted soon after and every year on her birthday, she receives a card simply signed with the letter G. Erica, as it turns out, has been investigating this tragedy for years. She begins to connect the dots and uncovers a sordid past involving adoptions that is more sinister than anyone had imagined.