
It all starts when Linnet Ridgeway, one of the richest young ladies in London, steals the fiancé of her best friend, Jacqueline de Bellefort. Linnet Ridgeway not only steals Simon Doyle away from her friend Jackie, but she marries Simon and they head off on their honeymoon to Egypt. In revenge for stealing her man, Jackie starts showing up at all the locations where the newlyweds are present and harasses them. Coincidentally, Hercule Poirot is vacationing in Egypt and boards the same ship to sail up the Nile that the Doyles and Jackie de Bellefort take.
While on board, Jackie shoots Simon Doyle in the leg one night in the saloon. On the same night, Linnet Doyle is shot in the head while she's sleeping. Hrecule Poirot takes on the case with his friend and fellow investigator who has come aboard the ship, Colonel Race. During the investigation, two more people are shot and killed, including Linnet's maid and one of the other passengers, Mrs. Otterbourne. Just in the nick of time, Hercule Poirot finds the murderers as the ship returns to port and justice triumphs.