Mary and Masaaki are parents-in-law. Masaaki was desperate to suppress her sexual desire for Mary, who is beautiful and close to her age, yet full of motherhood. However, Masaaki's spirit and body weakened enough to suppress his lust. Masaaki couldn't stand it and decided to leave the house, but finally the three parents and children decided to go on a hot spring trip. With this, Kippari and Masaaki should have cut off their feelings for Mary ...