Synopsis

One year after their divorce, Hamasaki Mitsuo (Eita) and Yuka (Ono Machiko) are still living together—though Mitsuo is secretly hoping to remarry her. As the year ends, the two visit a campsite, joined by Uehara Ryo (Ayano Go), who shares that Akari (Maki Yoko) has given birth and will return to Tokyo soon.

Afterward, Mitsuo and Yuka visit her family home, where Mitsuo announces his plans to remarry her—bringing their parents to tears. But despite the happy news, one major issue still stands between them.

Meanwhile, Ryo reunites with his first love, Shiomi Kaoru (Usuda Asami), who once broke his heart. When they meet again, Kaoru gives him a ticket for the nostalgic sleeper train “Cassiopeia,” rekindling old emotions.

At the same time, Kurobe Santoku (Okada Yoshinori), a kind-hearted single father and bento shop owner, develops feelings for Yuka—complicating things even more.

What surprises await aboard the legendary Cassiopeia? A journey full of emotional twists is about to unfold.