Chiharu and her husband had been abstaining from sex for 13 days in order to conceive a child. Today was Friday, the long-awaited ovulation day. Thanks to their abstinence, her libido was high, her sensitivity was at its peak, and it was the perfect day for conception. However, her boss, Oki, suddenly asked her to work overtime, and as Chiharu was working alone in the office, a terrifying masked man suddenly approached her... No matter how much she ran, the masked man chased after Chiharu, and as she frantically tried to escape...