In a world where herbivores and carnivores coexist within a modern, civilized society, the greatest taboo is the act of predation. At the prestigious Cherryton Academy, this peace is shattered by a brutal incident: Tem, an alpaca student, is murdered and devoured in the night, casting a dark shadow of fear and suspicion across the campus.

The story centers on Legoshi, a towering and introverted gray wolf. Despite his fearsome appearance, he is gentle and painfully self-aware, quietly working as the stage crew’s lighting operator for the drama club. His life becomes entangled with two individuals: the small, strong-willed white dwarf rabbit Haru, and the charismatic red deer Louis, who is the drama club’s star actor and an alpha among herbivores. Legoshi’s encounter with Haru awakens a confusing storm of emotions within him—he is unsure if his intense feelings for her are the stirrings of romantic love or his suppressed predatory instincts resurfacing. Louis, who secretly shares a complicated bond with Haru, dreams of becoming a Beastar, a prestigious title awarded to an animal of exemplary character who can bridge the divide between species.

The first season follows these three as they navigate the school's turbulent social landscape leading up to the Meteor Festival, a celebration of the planet’s ancient dinosaur ancestors. As Legoshi struggles to understand his nature, Haru is kidnapped by a gang of carnivorous lions from the black market, a seedy underbelly of society where meat is illegally sold. Forced to confront his limits, Legoshi ventures into this forbidden district to rescue her, an act that sets him on a collision course with his own identity.

In the second season, the pressure mounts as the unsolved case of Tem's murder continues to haunt the school. Determined to find the killer, Legoshi conducts his own investigation, a quest that leads him to a deeper understanding of the carnivorous hunger that society forces its members to hide. He trains under Gohin, a pragmatic and tough panda doctor who runs a clinic in the black market to rehabilitate carnivores who have succumbed to their instincts. The investigation ultimately reveals that the culprit is not an outsider but Riz, a seemingly gentle and friendly brown bear and a fellow student. Riz, who stopped taking his legal strength-suppressing medication, believed that eating his herbivore friend Tem was the ultimate act of bonding and understanding. The season culminates in a brutal, philosophical duel between Legoshi and Riz on a snowy New Year’s Eve, where Legoshi must decide how far he is willing to go to stop a predator who sees himself as a friend.

The final season shifts the conflict from the schoolyard to the wider, more volatile world. Having left Cherryton Academy, Legoshi attempts to live a simple life while pursuing a relationship with Haru, a pairing that society deems unnatural and dangerous. However, a new and more chaotic threat emerges in the form of Melon, a charismatic and deranged hybrid of a leopard and a gazelle. As a carnivore-herbivore hybrid, Melon embodies the very contradictions of their society and seeks to plunge the world into anarchy. As the black market grows more powerful and societal tensions reach a boiling point, Legoshi must confront this new adversary who has no respect for the natural order, fighting not just for his own future with Haru, but for the very meaning of coexistence in a world built on a fragile peace.