Samuel is a divorced classics professor traveling to visit his adult son. His scholarly work focuses on ancient history, and he spends much of his personal time overanalyzing past choices. He fears his capacity for passion has faded with age until an impulsive conversation interrupts his routine. He enjoys taking long walks around Rome with his son to visit locations of personal significance.

Miranda is a young career photographer who travels frequently for her work. She spends time caring for her ailing father, a retired professor who lives in Rome. She openly admits to growing bored easily in relationships, yet she initiates a fast-paced, intimate connection with an older man on her journey. Her direct communication style actively challenges hesitations in others.

Elio is a concert pianist and music teacher living in Paris. He dedicates his life to his art and heavily values his personal independence. He maintains a close bond with his father, often walking through Rome together to visit places tied to his romantic history. He retains strong, persistent memories of a summer romance from fifteen years prior.

Michel is a mature French lawyer who inherited his firm and a countryside estate from his deceased parents. He is divorced and has an estranged adult son. He believes heavily in fate and actively opens his life and home to a younger partner, even while recognizing that the connection might not be permanent.

Oliver is an American career academic preparing to move back to New Hampshire. Outwardly, he leads a conventional life as a married professor. Inwardly, he feels dissatisfied and frequently retreats into fantasies. A specific piece of piano music easily triggers intense memories of a summer he spent in Italy two decades earlier.

Micol is Oliver's wife. She manages the practical aspects of their household and considers herself part of a solid team with her husband. She knows Oliver had a profound experience in Italy years ago, but she remains unaware of the full extent of his internal dissatisfaction.

Paul works on the same floor as Oliver at a New York university, though in a different department. He attends Oliver's farewell party with his boyfriend. He plays classical music on the host's unused piano, inadvertently triggering deep memories for Oliver.

Erica is a beautiful woman Oliver knows from a local yoga class. She attends his farewell party, where she quickly connects with another guest over a shared acquaintance. She unknowingly becomes part of Oliver's internal fantasies as he longs for connections outside his established routine.

Adrien is Michel's deceased father. He frequently attended chamber-music concerts and left behind a customized musical composition. His hidden past prompts a modern investigation that uncovers historical secrets regarding his wartime connections.

Ariel is a historical musician who played piano for the Florian Quartet during the 1940s. He left behind an improvised musical score containing hidden melodies. His life and tragic death during World War II become the subject of a modern-day investigation.

Miss Margutta is a woman from Samuel's past. She represents a significant missed opportunity in his romantic history. A single verbal mistake ended their connection, leaving Samuel with lingering regrets decades later.