Hachiro is the mightiest monster of his kind, a Fear created with the sole purpose of striking terror into humanity. His entire existence takes an unexpected turn after a chance encounter with ice cream, which instantly makes him a devoted fan of human culture and sweets. This newfound appreciation earns him the anger and disdain of his fellow Fears, who view his affection for humans as a betrayal of their monstrous purpose. The story is set in Tokyo, where Hachiro must navigate his double life, keeping his true identity as a Fear a secret while working odd jobs to survive in the human world.

The central conflict arises from Hachiro rebelling against his overbearing creator and fighting off ghoulish foes, all while trying to enjoy human treats in peace. His motivation shifts dramatically when he witnesses the Unbelievables, a newly established mecha-suited unit of the Metro Police Department. Inspired by their heroism, Hachiro decides he wants to be just as cool as they are, leading him to question whether there are limits to what a monster can truly achieve.

In the first major narrative arc, Hachiro struggles to balance his monstrous nature with his admiration for humanity. He actively thwarts the schemes of other Fears and battles various ghoulish enemies, all while maintaining his cover. The story combines action and comedy, with plenty of electric fight scenes and humorous moments as this sweets-loving monster tries to fit in.

As the series progresses into its second volume, Hachiro finally succeeds in making a human friend. The complication is that this friend is none other than the leader of the elite squad specifically formed to combat Fears like Hachiro. This uneasy friendship is tested when Hachiro gets kidnapped by a powerful Fear named Jack the Fiend, forcing both Hachiro and his human allies to confront complicated questions about loyalty, identity, and whether a monster can truly become a hero.