Ayumi Arihara, a middle schooler who daydreams about being confessed to, gets a love letter from Misao Zaitsu, a hulking high school delinquent the girls nickname Beast-kun, and panics over how to answer him. Her friend Kei Enomoto, tired of the attention her mature looks draw, falls into a prickly back-and-forth with Etsu Kusuda. Around them, the rest of the group's first crushes tangle through the same small town.