Brother and his wife have remained in a sexless marriage, the cause being the brother's gaming addiction. As marital dissatisfaction grows, the sister-in-law begins to feel emotional emptiness. One day, she shows up at her brother-in-law's private apartment, saying, "Onii-san, living like this every day is so lonely... I might end up cheating if things don't change." From the moment she visits to rekindle the couple's bond, a new relationship begins to form...