Hotaru lives an ordinary life in a typical home, spending her days doing housework. One day, a young man appears who seems too youthful to be a match for her. In reality, he is her boyfriend, and the couple shares an age gap of about 30 years. Despite this imbalance, their relationship is so strong and affectionate that it draws admiration from those around them. However, Hotaru has never allowed her boyfriend to go beyond kissing, leaving him constantly frustrated and longing for more. One day, when the young man visits her home, he catches her with another person. This incident will shake the foundation of his heart like never before.