Aspiring manga artist Mizuho Nishino has grown alongside her four childhood friends: Kizuki Hazawa, Shuugo Hoshikawa, Shin Kashiwagi, and Airu Izumi. But on Mizuho's 17th birthday, Kizuki suddenly asks to be her boyfriend. Having no previous experience with romance, Mizuho brushes it off easily, but Kizuki is genuine and intends to win her heart.

Kizuki no longer hides his affections, and Mizuho hesitates, worried about the consequences their potential relationship could have on their whole friend group. As Mizuho works through the confusion of youth, it seems that the other three boys have fallen for her as well—and she must find a way to sort her feelings out without shattering the close-knit group she holds dear.