Uzuku gibo to musume: Nekojita kurabe(2003)

Sayuri has been dating Iwasaki for five years. It has been six months since he started looking for a job after the company he worked for went bankrupt. She has not been able to find a new job, and recently they have been quarreling over a few things. Then one day, Shizue, the remarried woman of Sayuri's father Kazuhiro, comes to Sayuri's house. That night, Sayuri, unable to bear the sound of Kazuhiro and Shizue's fierce desire for each other, leaves her room and runs into Shizue's stepson, Reiji, in the kitchen. He told her about Shizue's past, in which she had been with many men. He told her that Reiji was not Shizue's real child. Kazuhiro was away from home on a business trip the next day.