Twenty-year-old Houzaburo Ogasawara commands the Ayashi, a specialized monster-hunting unit within the government-backed Bansha Aratamesho. Tasked with combating supernatural Yōi threats in Edo-period Japan, he leverages his scholarly expertise in rangaku—the study of Western sciences and cultures during Japan's isolation—to inform his leadership and strategy. His position demands constant navigation of complex political dynamics, balancing the Ayashi's mission against conflicting demands from governmental authorities, creating persistent tension.