In a civilized society of anthropomorphic animals, an uneasy tension exists between carnivores and herbivores. At Cherryton Academy, this mutual distrust peaks after a predation incident results in the death of Tem, an alpaca in the school's drama club. Tem's friend Legoshi, a grey wolf in the stage crew, has been an object of fear for his whole life. In the immediate aftermath of the tragedy, he continues to lay low and hide his traits, much to the disapproval of Louis, a red deer and the domineering star actor of the drama club. When Louis sneaks into the auditorium to train Tem's replacement for an upcoming play, he assigns Legoshi to lookout duty. That very night, Legoshi has a fateful encounter with Haru, a white dwarf rabbit scorned by her peers. His growing feelings for Haru, complicated by his predatory instincts, force him to confront his own true nature, the circumstances surrounding the death of his friend, and the undercurrent of violence plaguing the world around him.

"Beastar"—a title awarded to beasts who prove their excellence through fighting inequality to unite carnivores and herbivores in an anthropomorphic animal society. Cherryton Academy has gone five years without one such leader. However, following the murder of an alpaca within the school boundaries, the growing tension between the different species poses a greater need for a Beastar to ensure peace and harmony. When Louis, the prime candidate for this prestigious role, rejects the offer and leaves the academy, the student council declares to honor any student who captures the culprit of the aforementioned murder as Beastar. Meanwhile, Legoshi's sense of duty as a strong wolf who must protect the weak pushes him to investigate the incident. To further complicate his life, he struggles to manage his complex feelings for the white rabbit, Haru.

Following the unmasking of the carnivorous murderer, Cherryton Academy introduces a segregation policy to protect herbivores, further fueling public disdain for carnivores. Meanwhile, the black market for meat thrives like never before, and the Shishi-gumi faces upheaval after losing their leader. A shadowy, violent figure emerges, intending to seize control of the Shishi-gumi with the introduction of an appetizing energy drink for carnivores. Having left school, Legoshi, a gentle gray wolf at odds with his predatory instincts, attempts to lead an unassuming life; he only uses his innate strength to protect the weak. However, his involvement with the academy's murder investigation draws the attention of the current Beastar—society's leading authority. For the sake of his controversial relationship with white dwarf rabbit Haru, Legoshi clings to his sense of justice, even when he sinks into the chaos caused by rising tensions between carnivores and herbivores.