In a land plagued by giant insects, the people of Edo plead for aid, leading to the formation of the Insect Magistrate Office. Jinbee Tsukishima, a young man determined to prove his strength as a warrior, aspires to join this elite group to redeem himself for a past tragedy. Along his path, he encounters Haru, a kind woman in need of rescue, showcasing his sword skills and securing his spot in the Insect Magistrate. Now, as a novice exterminator, Jinbee faces the daunting task of eradicating the insect horde threatening the realm.