The drama is set on the Twilight Express, Japan's longest overnight train service, which runs approximately 22 hours between Osaka and Sapporo. Nakayama and Sato play Chie and Keisuke, two lovers who have decided to part ways at the end of the journey. Chie already has a family but has been carrying on a passionate, secret affair with Keisuke. The story mainly takes place in their suite room on the train.
The drama was filmed aboard the actual Twilight Express with cooperation from the JR West company, which operates the train service.