Lin, a housewife in her fifth year of marriage, lives peacefully with her kind husband Kenichi's family, along with his equally kind "parents-in-law." However, Lin has one worry. Her elderly father-in-law, who lives with her, stares and behaves in a sexually harassing manner on a daily basis...! This is a thrilling drama about the forbidden, immoral infidelity between a son and his wife, focusing on situations such as "even though his mother-in-law is there" and "even though his kind mother-in-law is right next to him"...!