Third Girl Book by Agatha Christie

In "Third Girl" by Agatha Christie, Hercule Poirot is approached by a young woman named Norma Restarick, who believes she may have committed a murder but is unsure of the details. Poirot and his friend, Ariadne Oliver, become involved in the investigation, delving into the troubled lives of Norma and her roommates. As they uncover a complex web of secrets, past traumas, and psychological mysteries, Poirot works to determine whether a murder has indeed occurred and, if so, to identify the perpetrator.