Son goes on business trip, father-in-law and daughter-in-law secretly have incest

It's been several months since Akari, my beautiful daughter-in-law, moved in with my father-in-law, Shigeru. Taking advantage of the time I lived together, I started trying to get pregnant, something I tried for a long time but with little success. As a result of the examination at a fertility clinic, it was discovered that the husband had sperm problems. One day, the husband was scheduled to go on a business trip for 2 nights and 3 days. Akari and Shigeru are alone under the same roof.