Cartagra: Tsuki Gurui no Yamai

A washed-up ex-cop scraping by on odd detective jobs, Takashiro Shugo lives rent-free in a brothel in post-WWII Japan just to get by. When his former superior drops a missing persons case on him, it turns out the woman he's supposed to find is Yura — someone he was close to before the war tore everything apart. That alone would be enough of a premise, but while Shugo starts digging, a string of brutal murders starts creeping closer to his world. The mystery and the violence begin to overlap in ways that get genuinely unsettling. This is a 2-episode OVA adapted from a dark visual novel, so it moves fast and doesn't ease you in. The post-war setting gives everything a grimy, atmospheric weight — burned-out people in a burned-out country, and something predatory hiding underneath. If you've watched Kara no Shoujo and liked how it layered psychological dread over an investigation, this sits in similar territory. Fans of Yami no Koe will recognize the same blend of eroticism with genuinely dark horror underneath, rather than one being an afterthought to the other. The art style leans into the period mood well. Just know going in what it is — this is a hentai OVA, so the adult content is upfront, but the mystery threading through it has more substance than you might expect from the format.