Elio's father, Samuel, is on a trip from Florence to Rome to visit Elio, who has become a gifted classical pianist. A chance encounter on the train with a beautiful young woman upends Sami's plans and changes his life forever. Elio soon moves to Paris, where he, too, has a consequential affair, while Oliver, now a New England college professor with a family, suddenly finds himself contemplating a return trip across the Atlantic.