Tom Ripley is a young man struggling to make a living in New York City. When working at a party, playing the piano in a borrowed Princeton jacket, he is approached by the wealthy Herbert Greenleaf, who believes him to be a Princeton alumnus. He asks Tom to travel to Italy to persuade Greenleaf’s errant son, Dickie, to return to the United States. Ripley did not go to college at all and has never even met Dickie, but nevertheless goes along and agrees. Shortly after his arrival in Italy, Ripley meets Dickie Greenleaf and his girlfriend, Marge Sherwood. He quickly insinuates himself into their lives. Over time Dickie begins to tire of his new friend, resenting Ripley’s constant presence and growing dependence, especially after he learns that Tom has been lying about their days together at Princeton. Ripley’s feelings are complicated by his desire to maintain the wealthy lifestyle Greenleaf has afforded him and by his growing sexual obsession with his new friend.

As a gesture to Ripley, Greenleaf agrees to travel with him on a short holiday to Sanremo. The two hire a small boat and go sailing. They begin arguing while on board, with Dickie rejecting and mocking Ripley. Enraged, Ripley attacks Dickie, smashing him with an oar and, in the ensuing struggle, accidentally killing him. Horrified, lets the boat drift to shore with Dickie’s body in his arms. He then sinks the boat, with Dickie’s body still on board, to conceal his crime.