Rei Ichido, Go Reietsu, Kiyoshi Shusse, Jin Daima, and Dai Monohoshi are five mischievous boys attending Ichiou Junior High. Each with an eccentric personality and a knack for chaos, they've earned a reputation as the infamous "Kimen-gumi."

One day, new transfer student Yui Kawa and her friend Chie Uru encounter the group and soon find themselves drawn into their antics. Around them are other colorful cliques—from the handsome "Iro Otoko-gumi" led by Shou Kireide, to the delinquent "Ban-gumi" led by You Nihiruda, the athletic "Ude-gumi" led by Kai Undou, and the tough girl squad "Onna-gumi" led by Jako Amano.

As time passes and a new spring begins, the everyday lives of these eccentric students unfold in a lively and comedic school story.