The land of Edo is facing a severe threat from monstrous insects, creating havoc among the inhabitants. Ordinary people are powerless against these formidable creatures, so the Insect Magistrates, a specialized warrior community well-versed in secret arts and combat styles, are enlisted to take them down. To strengthen their already formidable skills, they summon Genjuurou Tsukishima, a master swordsman from the Tsugaru Province. Unfortunately, an incident renders Genjuurou unable to fulfill his duties, and he sends his son Jinbee in his place. Driven by his desire to make amends for the mistake he made, Jinbee agrees to join the Insect Magistrates and pledge to become a stronger samurai. Armed with an unbreakable spirit and determination, he embarks on a journey to rid Edo of this perilous insect threat once and for all.