Tom Ripley is an amoral, slightly disreputable young man, with no prospects, who occasionally moves in wealthy circles. Tom is approached by affluent shipyard owner Herbert Greenleaf, the father of an acquaintance who has lived in Italy for two years. Mr. Greenleaf wants Tom to travel to Europe and convince his son Dickie to return to the U.S. Ripley is armed with a first class ticket and enough cash for two months in Europe. Tom has fantasies of adopting the luxurious lifestyle of the Greenleafs. In Italy, Tom is attracted to Dickie and jealous of his close female friend, Marge Sherwood. Marge alienates Tom further by suggesting to Dickie that Tom is homosexual, an unthinkable sin in the 1950s. Dickie becomes cold, and it is obvious that unless he comes up with a plan, Tom's days living in luxury are numbered.

Tom develops a plot to kill Dickie and assume his identity, forging Dickie's signature to checks and other financial documents. The elaborate measures Tom must take to maintain both identities never degenerate into predictable farce in Highsmith's novel. When the police suspect Dickie of committing Tom's murder, Tom stages Dickie's "death," naming Tom Ripley sole heir in the will. Highsmith's novel is a vibrant exploration of 1950s Europe, fraught with latent homosexuality, class and identity issues, and a through exploration of the character of one amoral young man.

Dickie Greenleaf is initially cold to Tom Ripley when they meet in Italy. Greenleaf does not recall their New York meeting, and is perfectly happy with the routing of his life in Mongibello, a small village south of Naples. Finally, Tom admits that Dickie's father, Mr. Greenleaf, has sent him to Italy to convince Dickie to come home. Charmed by Tom's candor, Dickie invites Tom to stay in his villa, and the two soon become close. After Tom and Dickie spend a drunken night together in a park in Rome, Dickie's girlfriend, Marge Sherwood, becomes jealous. Marge and Dickie have an argument, and Marge accuses both Dickie and Tom of being homosexual. Horrified, Dickie denies Marge's accusation, and becomes cold and unfriendly towards Tom. Tom also denies being gay, but longs to spend the rest of his life with Dickie, traveling the world.

Tom and Dickie take one final trip together, visiting Cannes and San Remo. When Dickie humiliates him, Tom thinks of murdering his friend. Lacking the moral compass that keeps most people from acting on their worst impulses, Tom decides to kill Dickie Greenleaf and assume his identity. The two look enough alike that Tom is certain he can travel on Dickie's passport if he only lightens his hair. At Tom's suggestion, the two rent a small motorboat, and Tom bludgeons Dickie to death with an oar. The boat is bloodstained, so Tom scuttles it in a deserted cove.

Tom returns to Mongibello, telling Marge that Dickie has suddenly decided to stay in Rome to study painting. Tom arranges for Dickie's house, furniture and boat to be sold, telling everyone he is acting on Dickie's behalf. In Rome, Tom assumes Dickie's identity and rents an elegant apartment. Tom continues traveling on Dickie's passport, and forging Dickie's signature to his monthly trust fund income checks, for several months. When Freddie Miles, a close friend of Dickie's, suspects foul play, Tom kills him and dumps the body behind a tomb in Rome.

When Freddie's body and the bloodstained boat are discovered almost simultaneously, the authorities become suspicious that Dickie is a serial murderer. Since there is no legal record of Tom Ripley anywhere in the country since the trip to San Remo, the police believe he is dead. The banks in Naples and New York check their records and determine that someone is forging Dickie's signature.

Assuming the hated identity of Tom Ripley once again, Tom travels to Venice by car and convinces the authorities he has been motoring around the countryside for months. Dickie Greenleaf cannot be found, and the authorities believe he is in hiding. His father hires an American private detective to locate Dickie. When Dickie Greenleaf's luggage turns up abandoned at an American Express office, the detective, Marge and Mr. Greenleaf accept Tom's assertion that Dickie has probably killed himself. Tom forges a will he says Dickie gave him months ago, naming Tom Ripley as his sole heir. Heartbroken, the Greenleafs accede to their son's last request, and agree Tom Ripley will inherit Dickie's fortune. The Talented Mr. Ripley is an effective exploration of the inner thoughts of a sociopath, perfectly illustrating that sometimes crime does pay.