"The Grownup" is a psychological thriller by Gillian Flynn that delves into themes of deception, trust, and the supernatural. The story is narrated by a young woman who makes a living through fortune-telling. She presents herself as a reliable psychic but is primarily focused on conning her clients to earn money. Her life takes an unexpected turn when she meets a mysterious woman, Susan, who is troubled by strange occurrences in her home. This encounter sets off a chain of events that challenges her perception of reality and her own abilities.
As the narrator becomes more involved with Susan, she finds herself drawn into a web of secrets and fears surrounding the woman's haunted past. The tension escalates as the story unfolds, highlighting the fragility of trust and the dangers that come with manipulation. The protagonist must confront her own beliefs and face an unsettling truth about her life. Flynn expertly weaves suspense and psychological elements, keeping readers on edge as the plot twists and turns.