The setting is San Francisco, the present day. Nicky Hunter is a 30-something crime historian and lecturer, well-established in her field. She had struck up a correspondence with the famous and successful Sebastian Trapp five years previously, after writing him about a flaw in one of his novels, and now he’s invited Nicky to stay with him in his house while he writes his memoirs. Nicky is thrilled to have been invited but also wants to solve the story of Sebastian’s wife and son, who disappeared twenty years ago and have not been heard from since. Nicky believes she can coax ‘the truth’ out of him.
Nicky reviews the case files but is also lodging in the attic bedroom of the house, filled with memorabilia. She spends time with Sebastian, who is a larger-than-life character. Diana, Sebastian’s second wife, and Madeleine, his daughter, also live in the house. Nicky suspects them and others as possible suspects in the mystery.
A small parcel with an origami figure is left on the doorstep, leading everyone to believe it’s a message from Cole, Sebastian’s missing son. The story delves into the past, revealing that Cole was a sweet but bullied child who went missing with his mother, Hope, twenty years ago.
A party is organized, and during it, a confrontation with Freddy reveals shocking details about the past. Diana is later found dead in the garden, seemingly a suicide. The police investigate but find no proof of murder. Nicky later tracks down Freddy, who confesses to selling memorabilia to online obsessives. Madeleine receives texts from someone claiming to be Cole and begins to suspect if he’s really her brother.
The story takes surprising turns as Nicky reveals she is Cole, who transitioned to Nicky and tried to get closer to her father. Madeleine also confesses to killing Hope, which was a misunderstanding during an argument. Sebastian dies by suicide, and Madeleine is arrested for Hope’s death.
In the end, Nicky/ Cole returns to read Sebastian’s final novel, and the story is seen as a pastiche of various crime novels and films.