Young couple Takashi and Kannon have been married for half a year. They always wanted to have a child but Kannon couldn't because she was infertile. Coincidentally, Megumi - a flight attendant and Kannon's older sister, also wants to have a baby while the couple, due to work circumstances, cannot do it together often. The story began when Megumi visited her sister-in-law's house. After learning that Takashi was saving a large amount of sperm for his wife, she solicited her brother-in-law to help her because that day was her day. Ovulation. Although she repeatedly refused and advised her that it was completely wrong, she did not care at all. On the contrary, she boldly caressed his penis and even raped him while her sister was not paying attention. This will continue to happen during the ovulation days of next month if this lustful sister is not pregnant.
