The novel Third Girl was first published in 1966.
This time, Hercule Poirot is faced with a case far more peculiar than usual. It all begins with an unexpected visit and a seemingly absurd confession from a young woman named Norma Rastrick: “I might have committed a murder.” Although she immediately refuses Poirot’s services, considering him as too old, he decides to uncover the truth.

Each newly revealed fact complicates the case further, transforming what initially seemed to be a plain situation into a complex series of events and motives. Step by step, by examining the people involved and uncovering the true reasons behind their actions, Poirot manages to put together the entire puzzle—leading the reader to a completely unexpected conclusion.