Takashi and his wife Kanon are in their second year of marriage. They want a child, so they try to get pregnant by having Takashi abstain from sex for a month so that he can produce healthy sperm just before ovulation, which is the time when it is easiest to get pregnant. Meanwhile, Kanon's older sister Megumi is a flight attendant and travels around all over the country, so she has not been able to have a child with her husband. Wanting a child before her sister, Megumi comes to seduce Takashi as the due date for her sister and her husband to have a child approaches, and steals all of the sperm he has worked so hard to save up.