Ten years into a cold, loveless marriage, Ryo is approached on the street by Haneda, a childhood friend who had a crush on her twenty years ago. He has grown into a handsome, muscular man she barely recognizes. When he visits in the rain while her husband is away, she lets him take a shower and accidentally catches sight of his huge cock. Stunned by how different it is from the tiny one she remembers from their childhood baths, Ryo loses control and becomes hooked on having condomless sex with him again and again.