Tetsuo Amano serves as a train conductor for the Kankyuu Railroad company on the Momokawa Line, vital to his hometown's existence. He dreads the line's possible shutdown due to financial instability, convinced this would accelerate the town's decline as younger residents depart for urban jobs. This economic threat drives his actions.

Partnering with colleagues Makoto and Inoue, Tetsuo spearheads an unconventional business strategy to improve the train line's profitability. Their plan repurposes late-night trains into settings that enable non-consensual sexual encounters among passengers. Tetsuo personally participates, utilizing a specific manual technique derived from his own experiences. He adheres to a self-imposed code prioritizing the elicitation of physical pleasure in targets over overt violence, which he claims to despise. His method is described as nearly supernatural in effectiveness, reportedly preventing victims from crying out and sometimes provoking further involuntary physical reactions.

He uses this technique to identify women he believes might participate in group encounters within the altered trains. While acknowledging the scheme's immorality, Tetsuo rationalizes it as essential for the town's survival and perceives no fundamental wrong in his own conduct. A significant personal conflict arises from his fear that childhood friend Sana might uncover his activities, generating intense anxiety about facing her judgment and shattering their longstanding relationship. His professional dedication to preserving the train service is intrinsically bound to these illicit acts, forming the core of his depicted motivations and internal struggles.