Sayo and Masanao are childhood friends who have known each other for 60 years and are celebrating their 33rd anniversary this year. Both have semi-retired from their companies and are about to become grandparents. They embark on a hot spring trip to start their second lives together. The skin-to-skin contact in the bath, the eroticism of their mature bodies, and the love that overflows with each embrace—experience the ultimate sex of a mature couple.