Two high school students, Mizuho Yuuki and Miko Kamiyama, have an unwavering and strong friendship. Miko has developed feelings for their fellow classmate Tohru Nagase, and Mizuho respects her friend's affection and promises not to interfere. However, Tohru now has to choose between Miko and their younger classmate, Ai Minamizato, who also has feelings for him. It is Tohru's responsibility to decide whom he has stronger feelings for.