Poirot is a renowned Belgian detective known for his sharp psychological insight and careful attention to detail. Currently on vacation in Egypt, he hopes to enjoy a quiet winter trip but finds himself continually drawn to the tensions among his fellow travelers. He takes a particular interest in the desperate behavior of Jackie de Bellefort, attempting to counsel her away from a dark path.

Linnet is a beautiful, twenty-year-old heiress with a massive fortune and a clear-cut business mind. She is accustomed to being the center of attention and confidently orchestrates the lives of those around her. Though she claims to have no enemies, her immense wealth and her sudden marriage to her best friend's former fiancé create a thick cloud of envy and bitterness directed at her.

Jackie is the broke but intensely proud daughter of a French count and an American southerner. She refuses financial charity from her wealthy best friend, Linnet, but asks for help securing employment for her beloved Simon. After Simon leaves her to marry Linnet, Jackie becomes dangerously fixated, following the newlyweds across the globe to enact relentless psychological revenge.

Simon is a tall, broad-shouldered young man with crisp brown hair and a boyish smile. Initially penniless and engaged to Jackie, he readily accepts a job as Linnet's land agent. He quickly breaks his engagement to marry the wealthy heiress instead, enjoying the comforts her money provides while trying to shield her from his ex-fiancée's harassment.

Tim is a tall, delicate young man traveling with his mother to manage his frail health. He lacks a steady occupation and claims to dabble in writing. He shows an intense, unexplained wariness whenever the detective Hercule Poirot is present and maintains a steady stream of letters with his socialite cousin.

Mrs. Allerton is a good-looking, white-haired woman traveling to escape the English winter. She is socially adept, tolerant, and well-liked by nearly everyone she meets on the journey. She harbors quiet anxieties about her son's health and his close association with their superficial relative, Joanna Southwood.

Miss Van Schuyler is a wealthy, elderly woman with a wrinkled face and a stiff posture. She views most people with reptilian contempt and expects total submission from her dependents. She demands constant attention and requires the steady presence of her professional nurse during her travels.

Cornelia is a large, clumsy young woman with eager brown eyes and a desperate willingness to please. Serving as an unpaid social companion to her demanding relative, she remains remarkably cheerful and genuinely interested in the Egyptian historical sites. Her father was financially ruined by Linnet's father years ago, a fact she handles with surprising grace.

Pennington is Linnet's American uncle and the primary trustee of her vast fortune. Tall, spare, and possessing a ruthless jaw, he dresses impeccably and projects the image of a successful Wall Street lawyer. He orchestrates a "coincidental" meeting with Linnet in Egypt, carrying a stack of complex legal documents he hopes she will sign without reading.

Mrs. Otterbourne is a once-famous novelist who dresses in dramatic black draperies and speaks in a high, complaining voice. She constantly exaggerates her own cultural importance and berates her daughter for a perceived lack of sympathy. She battles a severe, hidden illness that drives her to seek out the ship's crew at odd hours.

Rosalie is a striking young woman who constantly wears a bad-tempered, sulky expression. She harbors a deep, secret anxiety regarding her mother's behavior, leading her to isolate herself from the other passengers. She initially views Linnet with intense hatred, feeling that it is unfair for one person to have money, beauty, and love.

Joanna is a tall, thin aristocrat with freakishly plucked eyebrows and a long clever face. She makes no secret of the fact that she abandons friends the moment they lose their money. She lives a luxurious life despite claiming to be broke and frequently features in society gossip columns.

Miss Bowers is a thin, practical nurse who wears pince-nez glasses. She attends strictly to the demands of Miss Van Schuyler, serving as a constant supervisor and personal assistant to prevent her employer from engaging in problematic behaviors during their travels.

Carmichael is the senior partner at Carmichael, Grant & Carmichael and serves as Linnet's British solicitor. He possesses a sharp legal mind and immediately suspects foul play when he learns that Linnet's American trustee has coincidentally met her in Egypt.

Fanthorp is an intensely quiet, cautious young British lawyer who wears an Old Etonian tie. He travels to Egypt on his uncle's orders, blending in with the tourists while keeping a close, protective eye on the legal documents Andrew Pennington presents to Linnet.

Dr. Bessner is a stout, closely shaved German doctor who travels with a collection of guidebooks. He enjoys reading aloud from his texts and takes a strong, protective interest in Cornelia Robson, treating her far better than her own family does.

Ferguson is an aggressive, highly vocal young man who claims to be studying social conditions rather than vacationing. He despises the wealthy passengers aboard the ship, frequently suggesting they ought to be shot for their uselessness, though he develops a soft spot for Cornelia Robson.

Fleetwood is a big, truculent-looking engineer working aboard the Karnak. His plans to marry Linnet's former maid were destroyed when Linnet uncovered his existing marriage, leaving him deeply embittered and vocal about his desire for revenge.

Race is a sturdy British officer operating on government business. He boards the steamer specifically to track down a dangerous, clever political agitator responsible for multiple murders. He relies on Poirot's expertise when their respective investigations overlap.

Richetti is a highly talkative man traveling as an archaeologist. He displays sudden, intense fury when his privacy is violated, reacting aggressively when a telegram addressed to him is accidentally opened by another passenger.

Louise is Linnet's newly hired French maid, a dark and vivacious brunette. She handles Linnet's expensive belongings daily but displays signs of profound fear mixed with cunning when questioned by authorities about her nightly activities.

Marie is Linnet's former maid. Her life is disrupted when Linnet investigates the background of the man Marie intends to marry, discovering he already has a family in Egypt.