Having now mostly retired from his life of crime, Tom Ripley spends his days tending his garden and playing the harpsichord at his French home near Fontainbleau which he shares with his wife, Heloise. However, the calm and serenity of his life is shattered when obnoxious American David Pritchard arrives on the scene with his submissive, pathetically dysfunctional wife Janice. Pritchard is a decidedly eccentric stalker and heckler who has delved into Ripley's nefarious past. His current obsession is the disappearance of Thomas Murchison, an art collector whom Ripley murdered in Ripley Under Ground when he threatened to blow the lid off Ripley's art forgery scheme.
Pritchard initially harasses Ripley by talking about his knowledge of the suspicious death of Dickie Greenleaf (whom Ripley murdered in The Talented Mr. Ripley), photographing his house and following him on a trip to Tangier. While in Tangier, Ripley gets into a fight with Pritchard in a bar. Upon returning to France, Pritchard becomes a serious threat when he starts dragging local canals for Murchison's corpse and finally locates it. Pritchard dumps the skeletonized remains on Ripley's doorstep and then calls the police. Ripley finds and stashes the headless body before they arrive. That night, Ripley takes the remains to the Pritchards' temporary home nearby and dumps it in the pond outside. The Pritchards hear the splash and come out to investigate. They subsequently fall in while trying to hook the body with a garden tool. Both are apparently unable to swim and perish together in a mere two meters of water and muck. Police investigate but come up empty-handed. Ripley safely disposes of the last piece of evidence connecting him with Murchison, and the final installment of the Ripliad comes to a close.