Crimson Girls: Chikan Shihai

Calling themselves the Crimson Girls, Kuroha Mitsu and Nanase Saki are a duo riding public transit specifically to catch train gropers in the act. It's a vigilante setup with a clear moral compass. Then the series flips it on them hard. A man with an unsettling ability to manipulate sensation through touch starts targeting Mitsu herself, using the crowded train environment she knows so well as the trap. What starts as a straightforward premise about protectors becomes something considerably darker and more psychologically uncomfortable as Mitsu finds herself caught in exactly the kind of situation she's spent her time preventing. The tension comes from that reversal — watching someone competent and purposeful get systematically outmaneuvered by someone who's done his homework on her. The urban setting, packed commuter trains, anonymous crowds — it all works against her in ways that feel deliberate and unsettling. This is a three-episode OVA from 2012, adapted from manga, so it moves quickly and doesn't waste time on setup. The character designs are distinctive and the production quality holds up reasonably well for the format. If you've watched things like Discipline: Record of a Crusade or Bible Black and appreciated their darker psychological undercurrents, this sits in similar territory. It's not subtle about what it is, but within the hentai OVA space, the antagonist setup and the role-reversal premise give it more narrative structure than most.