Maki has been married for 12 years and her married life is cold. One day, on the street, she is approached by a man she doesn't recognize. The man is Kuroda, Maki's childhood friend from 20 years ago who had a crush on her. He has grown into a handsome, strong man, with no trace of his former self. While her husband is away, Kuroda comes to visit her in the rain and Maki lends him her shower, and by chance, she sees his genitals. Maki loses her senses at the sight of Kuroda's large penis, which is completely different from the small one she saw when they bathed together as children...