Mother embraced by her daughter's boyfriend

Yuki is on a business trip and lives with her only daughter, Kana. One morning, when Kana said to her, "Can I bring my boyfriend today?" Yuki was excited to see what kind of boyfriend would come to her house, and was also excited about cleaning. Then, in the afternoon, Kana returns home with her boyfriend Norihiko. A locked room for only two men and women of their age. Yuki never knew such a tragedy would lie in a few minutes. That tragedy that turns Yuki from her mother to a woman...