Early one morning, a young, eccentric woman named Norma Restarick knocked on the door of the famous detective Hercule Poirot and asked to see him. She looked unwell: frightened, nervous, and unstable. From her vague explanations, only one thing could be deduced: she believed she had committed murder. However, she couldn't recall the victim's name, the circumstances of the murder, or the crime scene. The killer existed, but the crime itself had not been discovered. It would be up to Hercule Poirot to find the crime.