SPOILER ALERT !!! While on holiday in Cairo, Hercule Poirot is approached by successful socialite Linnet Doyle. She requests his help in deterring her friend Jacqueline de Bellefort from hounding and stalking her. Linnet had recently married Jacqueline's fiancé, Simon Doyle, which has made Jacqueline bitterly resentful. Poirot refuses the request, but attempts unsuccessfully to dissuade Jacqueline from pursuing her plans further. Simon and Linnet secretly board the steamer Karnak, set to tour along the Nile, to escape her, but find she had learned of their plans and boarded ahead of them. Apart from them, Poirot travels on the steamer, while the other passengers include Linnet's maid Louise Bourget, her trustee Andrew Pennington, romance novelist Salome Otterbourne (a thinly-disguised portrayal of Elinor Glynn) and her daughter Rosalie, Tim Allerton and his mother Mrs. Allerton, American socialite Marie Van Schuyler, her cousin Cornelia Robson and her nurse Miss Bowers, outspoken communist Mr. Ferguson, Italian archaeologist Guido Richetti, solicitor Jim Fanthorp, and physician Dr. Bessner. While visiting an ancient temple, Linnet narrowly avoids being crushed by a falling rock. Jacqueline is initially suspected, but she is found to have been aboard the steamer at the time of the incident. During the return voyage, Poirot finds his friend Colonel Race has joined the steamer. He reveals to him that he seeks a murderer amongst the passengers. Later that night in the steamer's lounge, Jacqueline's resentment of Linnet boils over, leading her to shoot Simon in the leg with a pistol she possesses. She is taken back to her cabin by those who witness this, where she is confined, while Simon is treated for his injury; in that time, Jacqueline's pistol, which she dropped, disappears. The following morning, Linnet is found dead, having been shot in the head, while her valuable string of pearls has disappeared. No one in the cabins on the opposite side heard or saw anything. Poirot notes two bottles of nail polish in the victim's room, one of which intrigues him. Jacqueline's pistol is later recovered from the Nile; it is found wrapped in a stole belonging to Miss Van Schuyler, which was stolen the previous day, and which has been fired through.