After the affair, Keiji presses Yoshiko to marry him, but Yoshiko refuses because she is concerned about the fact that she is older than Keiji. Meanwhile, Yoshiko is selected as the secretary of the new company president, Okawa, and she is invited by Okawa to his villa in Izu. She was told to find a replacement for her private driver, who is currently on vacation, and she recommended Keiji.

Takashi Shirakawa, the president of Tozai Corporation, is an adopted son-in-law. His wife, Reiko, is sickly and their married life is indifferent. His secretary, Mitsuko Mizukami, who has been having a physical relationship with the president, is an adulterous woman who plans to seduce the president into letting her wife commit suicide so that he can get his wife Meigi's fortune.

拓哉打算和女友京子跨越最后一道防线时，没想到京子却说拓哉的性器官很可爱，京子让拓哉深受打击，两人的初体验不欢而散。 此时，拓哉的学长西川找他去兜风，从箱根出发往伊豆的途中，西川结识了一位名叫真理的女子，西川为了想和真理有进一步的关係，便谎称车子抛锚无法上路，要求拓哉去附近寻找住宿的场所。 三人还在路上出手相救了遭恶男调戏的藤子，原来藤子是经营小木屋民宿的老闆娘，于是三人顺理成章住进了藤子的小木屋...