It has been a few months since my beautiful daughter-in-law Akari moved in with my father-in-law, Shigeru. Taking advantage of our cohabitation, I started trying to get pregnant, something I had been trying for a long time without much success. After a check-up at an infertility clinic, it was discovered that my husband had a sperm problem. One day, my husband was scheduled to go on a business trip for 2 nights and 3 days. Akari and Shigeru were alone under the same roof.