Seiji Ino holds the position of underboss within the Kioi yakuza family, operating from Shibuya. He lives with severe trypanophobia, an intense fear encompassing sharp objects like needles, scissors, knives, and pens. This phobia manifests so powerfully it prevents him from using chopsticks, forcing him to rely solely on a spoon for eating. His common-law wife recognizes the debilitating nature of his condition and actively encourages him to pursue psychiatric evaluation.

During treatment, exposure therapy is recommended, involving deliberate encounters with feared objects to build tolerance. Initial attempts using sunglasses to mitigate the fear prove ineffective because of their sharp temple tips. He then tries swim goggles, which offer partial relief but not a full solution. His professional duties as underboss intersect with this personal struggle when territorial conflicts repeatedly bring him face-to-face with Yasu, a member of a rival yakuza group. These encounters escalate tensions, especially after an action by Ino's girlfriend inadvertently worsens the rivalry. The dynamic changes significantly when Ino discovers Yasu also contends with an obsessive-compulsive disorder. This shared experience of psychological challenges unexpectedly forges a friendship between the former enemies. Through their interactions, Ino cultivates greater empathy regarding mental health struggles.