After losing his job and being kicked out of his home, young man Takahiro is allowed to stay at his brother's house until he finds a new job. However, he feels unwanted even at his brother's house and is constantly berated by his brother for being a 30-year-old virgin. Wanting to gain confidence, Takahiro asks his sister-in-law, Mahiro, to take his virginity. Sympathizing with Takahiro, Mahiro agrees to have sex with him, but the moment he enters her, she is overwhelmed by a tingling sensation of pleasure.