You're Makoto Rin, and you have five brothers: Sho, Shinichi, Masato, Jikai, and Haru, all of whom attend the same school as you. Each of them is a year older than you. Collectively, your brothers are known as the "H5" because they're regarded as the most attractive boys in the school. Many girls feel resentment towards you due to your close bond with them. While they receive numerous prom invitations, you don't. They're often showered with gifts, whereas you aren't. This often leads you to feel as though you don't fit into their world.

On Valentine's Day, you notice many couples in the hallway exchanging chocolates. Your brothers also have been invited to accompany various girls to prom. As you step outside the classroom, you see that the festival has already commenced in the sports field under the moonlight. Couples and friends are gathering and enjoying the festivities while you stand by the window, listening to the laughter of boys and girls.