Love on the Run

Antoine and Christine are amid divorce proceedings, sharing custody of their son Alphonse. Antoine begins dating Sabine, a record shop clerk.

As they leave the courthouse after finalizing the divorce, Colette spots Antoine. Her curiosity grows when she learns he wrote a semi-autobiographical novel about their past.

At the Gare de Lyon, Colette boards a train to Aix-en-Provence while Antoine is there to drop off Alphonse for a summer music camp. He phones Sabine to tell her he can't attend her friend's party, explaining his obligations.

Sabine expresses interest in meeting Alphonse, but Antoine insists it is too soon. He accuses her of secrecy as he hangs up.

Antoine leaps aboard Colette's moving train, and she is startled by the reunion. The chance meeting sends their voyage into a tangled new phase.

Colette reads Antoine's semi-autobiographical book and discovers he has edited events of his life, including their past relationship, to appear less desperate. The editing shows a self-serving portrait that minimizes their history.

In the dining car, Antoine surprises Colette and they talk. He explains how he met Sabine after a torn photo was repaired and how he tracked Sabine to the record shop.

Colette becomes frustrated with Antoine's self-centeredness and refuses his kiss. As he sneaks away from the moving train, Sabine's photo slips from his grip, and Colette saves it.

Antoine visits Sabine to apologize for hanging up, but she returns the letters he wrote. He realizes that to salvage the relationship he must reveal how he knew Sabine, yet the photograph is lost.

At his workplace, Antoine is tracked by Lucien, the lover of his mother, who escorts him to her grave—a place Antoine admits he had never really searched. The encounter forces him to confront a missing piece of his family history.

Colette studies the photo's inscription and learns Sabine shares a last name with Xavier. She initially assumes Sabine is Xavier's wife, but later discovers she is his sister.

Colette meets Christine on Sabine's stairs and learns about Antoine's infidelities; Christine explains she divorced him after catching him with a friend, while Colette reveals her own tragedy.

Realizing she must tell Xavier she loves him, Colette hands Sabine's photo to Christine and heads to the bookstore to join Xavier, where they share a kiss.

Christine mails the photograph to Antoine, who shows it to Sabine and finally reveals how their love began. Sabine forgives and they kiss, concluding the reconciliation.