Rei Ichidou, Gou 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.

I'm Rei Hitoma, a self-professed misanthrope thanks to some past trauma. Just when I thought my new teaching job in the mountains would provide a chill, rejuvenating environment, it turns out that this school is actually for demi-humans who want to become full-fledged human beings! There's a mermaid, a werewolf, a rabbit, and a bird...all of whom are now my charges. It's my duty to teach them about humankind—and maybe in the process, I'll learn a few things myself. This isn't an alternate world or a case of reincarnation. It's just the story of a teacher at a somewhat peculiar school, and his students who are striving to become human.

On the day before her downfall, Lady Tiararose Lapis Clementille recalls that she is in an otome game that she had once played in her former life. She used to adore the main love interest Prince Hartknights Lapis-Lazuli Lactomuth, but unfortunately, she was not reincarnated as the heroine, but rather as is his worst enemy—the villainess fiancée. At their graduation ceremony, without blinking an eye, Hartknights condemns Tiararose for alleged crimes, breaks off his engagement, and proclaims the heroine Akari as his new bride-to-be. No matter whether Tiararose is innocent, he banishes her from the kingdom. But before her sentence can be carried out, a shocking figure appears. Aquasteed Marineforest, the prince of a powerful neighboring country, has been harboring feelings for Tiararose for quite some time, and announces his intention to marry her! Adored by the prince of another kingdom, what awaits the villainess on her path to a happy ending?

Next to Miyu Suzuki, a trendy and bubbly high school girl, sits Yuusuke Tani, a quiet and frank boy. Their interactions are brief, limited to Suzuki's unprompted random questions and Tani's succinct answers. Yet, beneath these simple exchanges, feelings of love are quietly blossoming. Suzuki sees Tani for who he is: a straightforward boy who respects everyone equally, completely unconcerned about fitting in. Unlike Tani, she is too hung up on what everyone else thinks, desperate to keep her crush a secret. However, a slight misunderstanding leads to Suzuki confessing her feelings—and to her delight, Tani feels the same. Jittery with excitement, the young couple starts dating, embarking on a wonderful journey of friendship and love.