Hercule Poirot is taking a holiday in Egypt, drifting up the Nile aboard the steamer Karnak among a cast of strangers thrown together by chance. Foremost among them is Linnet Ridgeway, a young, dazzlingly wealthy heiress, newly married to the handsome Simon Doyle. Their honeymoon, however, is shadowed at every stop by Jacqueline de Bellefort, Linnet's former friend and Simon's discarded fiancee, who trails the couple from hotel to temple to riverboat with an intensity that curdles into menace. The other passengers carry their own grievances and secrets: a trustee whose accounts may not bear scrutiny, a kleptomaniac dowager and her companion, a fading novelist and her watchful daughter, a mother and son with reasons to stay close to the rich. When a shot rings out in the dark and one of the party is found dead in a locked cabin, Poirot, aided by the soldierly Colonel Race, must untangle a knot of jealousy, money, and old wounds. Everyone aboard had motive; few had opportunity; and the obvious answer is the one Poirot trusts least. Drawing on Christie's own voyages along the Nile, the novel sets a tightly constructed puzzle against the heat and grandeur of ancient Egypt, where the detective sifts every alibi until the truth surfaces.