After 40 years of marriage, the devoted Sawa couple have been living a quiet retired life since husband Kenzo's retirement. To celebrate their 40th wedding anniversary, they embark on a trip together, a hot spring getaway gifted by their son Tadashi. No longer just husband and wife, they have grown into partners who have shared decades of joy and hardship. During their journey, the long-separated couple rekindle their emotional and physical intimacy, forging a renewed bond between them.