Momona's fiancé is a failure, he drinks, gambles, smokes all the way, abandons his fiancée to avoid debt. Since then, Momona has not left the house, her face always shining with sadness. Today, Momona's sister Sayuri brought her boyfriend to play at home for the first time. Tsubasa was attracted to Momona's huge breasts from the first time they met. Maybe because she hadn't been in contact with a man for a long time, Momona knew that Tsubasa was looking at her breasts but didn't hide it and deliberately let him see it. Seeing the cock in Tsubasa's pants made Momona's long-buried fever rise. And when the two met in the bathroom, Momona couldn't hold back anymore and took the initiative to suck Tsubasa's cock. And just like that, their clandestine relationship begins. The two constantly fuck each other whenever possible even though Sayuri is still right next to her...