Chris, a high school teacher, becomes the stepbrother of Wataru when his father remarries. However, tragedy strikes when their parents die suddenly in an accident, leaving the two to live together. As time passes, they fall in love with each other. Wataru continues to live with Chris, even during his second year of college. Meanwhile, Rei, a childhood friend of Wataru who used to have feelings for him, begins to develop feelings for Yamada, who has always secretly had a crush on Chris. Adding to the already complicated situation!