Kaori frequently brings her beloved boyfriend Atsushi to her parents' house because she doesn't have enough money for dates. Her mother, Saki, welcomes Atsushi. They seem like a happy couple, but in reality, Atsushi and Saki have been having a physical relationship behind Kaori's back. The two continue their relationship in secret so Kaori doesn't find out, but one day, Kaori notices their relationship when she peeks at Atsushi's smartphone.