The Cuckoo's Calling recap

Down-on-his-luck private investigator Cormoran Strike is hired by solicitor John Bristow to revisit the apparent suicide of John's adopted sister, the model Lula Landry. Assisted by his resourceful temporary secretary Robin Ellacott, Strike interviews Lula's neighbors, friends, family, and professional circle. He discovers that Lula had found her biological half-brother, Jonah Agyeman, and made a will in Jonah's favor. John, who expected to benefit from Lula's death, killed her and manipulated the scene; he had also killed his brother Charlie in childhood and later murdered Lula's friend Rochelle. Strike survives John's attempt to silence him and exposes the crimes. Jonah receives Lula's fortune, while Robin elects to remain at Strike's struggling agency, turning a temporary placement into a detective partnership.

Cormoran Strike begins the novel newly separated from Charlotte Campbell, sleeping in his London office, in debt, and concealing the practical difficulties caused by the loss of part of his leg in Afghanistan. Robin Ellacott arrives as a temporary secretary on the morning after the breakup. John Bristow then offers Strike a well-paid case: his adopted sister, the famous model Lula Landry, fell from her balcony, and police ruled the death a suicide. John believes a suspicious man near the building was overlooked. He also reminds Strike that his brother Charlie, who died as a child, was once Strike's friend. Strike is doubtful of John's theory but needs the fee and agrees to review the evidence. Robin, delighted by the unexpected proximity to detective work, begins imposing order on the failing agency.

Strike examines Lula's luxury apartment building and interviews the people connected with the night of her death. Security guard Derrick Wilson describes the building's alarms and movements, while neighbor Tansy Bestigui maintains that she heard Lula arguing with a man. Lula's troubled boyfriend Evan Duffield had quarreled with her but appears to have been elsewhere when she fell. The press treated Lula's recent psychiatric problems and her relationship with Duffield as an easy explanation for suicide. Strike is less convinced, particularly because the witness accounts and timing do not fit neatly together. Robin proves useful at research and at handling interview arrangements, and Strike starts trusting her with more than routine office work despite Matthew's unease about her new job.

The inquiry widens beyond the apartment. Designer Guy Somé describes Lula's intelligence, loyalties, and conflicts within the fashion world. Strike also speaks with Lula's driver, acquaintances, and adoptive family, learning that she had become intensely interested in locating her biological relatives. Rochelle Onifade, a vulnerable friend linked to Lula's birth mother, confirms parts of that private search but is evasive about their last meetings. Strike comes to believe that Lula's activities before her death mattered more than her public relationship with Duffield. Meanwhile Robin becomes increasingly committed to the case and demonstrates an ability to obtain information without alarming people, making her difficult for Strike to dismiss when the temporary contract approaches its end.

Strike reconstructs Lula's final day through interviews and telephone records. Her contacts with friends and family point toward a discovery she intended to formalize, while several people around her had financial or personal reasons to control what she did. Rochelle's knowledge makes her an important witness, but she is found dead before Strike can secure a full account, and her death strengthens his belief that Lula was murdered. The apparent stranger near Lula's building can no longer be treated as the whole explanation. Strike begins concentrating on access, inheritance, and the possibility that the killer was someone whom Lula would willingly admit to her flat.

Lula had succeeded in finding Jonah Agyeman, her half-brother through her biological father. She met him secretly and intended him, rather than the Bristows, to benefit from her estate. Strike locates evidence of a valid will in Jonah's favor and resolves contradictions in the accounts of the apartment building. The investigation now points away from Duffield and the celebrity circle. John Bristow's intimate knowledge of Lula, his financial interest, and his repeated efforts to direct Strike toward an unknown outsider take on a different meaning. Strike prepares a confrontation after making arrangements for Robin's safety and for the evidence to survive him.

Strike confronts John Bristow as Lula's murderer. John killed his brother Charlie when they were children and later pushed Lula from her balcony because her will left her fortune to Jonah Agyeman, destroying John's expected inheritance. He used his familiarity with the building and the confusion of the night to make the death resemble suicide, then killed Rochelle when her knowledge threatened him. John attacks Strike, but Strike overpowers him and the case against John is established. Jonah becomes Lula's heir. The successful investigation improves Strike's prospects, and Robin decides not to leave when her temporary placement finishes. Although Matthew dislikes the arrangement and the agency remains financially uncertain, Robin and Strike begin a durable professional partnership.

Strike concludes that John Bristow killed Lula. John had also caused the childhood death of his brother Charlie, and Lula's newly discovered will threatened John's expectation of inheriting her fortune by leaving it to her biological half-brother, Jonah Agyeman. John pushed Lula from her balcony, then exploited the layout and timing at the building to support a verdict of suicide. He later murdered Rochelle Onifade when she became a danger to him. John attacks Strike when confronted, but Strike overpowers him and the evidence brings the case to a close. Jonah inherits Lula's estate. Robin's temporary assignment ends, yet she chooses to stay with the agency despite its uncertain finances and Matthew's reservations. Strike, paid for solving the case and beginning to regain professional standing, gives Robin the green dress she admired, establishing the partnership that continues beyond the novel.