Mikagura Tanteidan

When their boss goes missing, three women travel overseas to find him, only to stumble onto a mutilated corpse in a church instead. That's the setup for Mikagura Tanteidan, a 3-episode OVA from 2004 that mixes genuine mystery with adult content, all wrapped in a Taisho-era period setting that gives it a distinct early 20th-century Japanese aesthetic. Mikagura Tokito, the head of a respected detective agency, vanishes after an accident, and his devoted associates — Tomoe, Shigeno, and Chizuru — aren't the type to just wait around. A tip puts Tokito near a foreign church, and when they arrive, they find a priest with his arms severed and a mystery that clearly runs deeper than a simple disappearance. The historical backdrop actually does some work here, giving the investigation a slower, more atmospheric feel compared to modern-set adult anime. If you've watched something like Bible Black or Discipline: The Record of a Crusade and appreciated when these titles bother to build a real story around the adult content, this one's in that same lane. The source material is a visual novel by ELF, and that origin shows — there's actual narrative structure and character motivation driving things forward rather than scenes just strung together. It's not going to reinvent the genre, but for a short OVA with a detective mystery framing and a period setting that actually commits to the atmosphere, it does more than you'd expect.