Mystery of Nonomura Hospital

Working as a private detective, Takumaro Kaibara is genuinely good at his job — and also genuinely insufferable around women. When the widow of a hospital director hires him to look into her husband's suspicious death, Takumaro does what any respectable investigator would do: fakes an injury to get admitted as a patient, then spends equal energy solving the case and bothering the nursing staff. That's the whole guy. Brilliant and completely incorrigible in the same breath. The mystery itself is a two-episode OVA adapted from a visual novel, set almost entirely within Nonomura Hospital. Someone died — officially a suicide, almost certainly not — and the internal politics of the hospital make everyone a potential suspect. Throw in a rival investigator from a competing agency who's also on the case, and Takumaro actually has to work for once. The adult content is upfront and present, so no surprises there, but the mystery framing gives it more structure than you'd expect from something in this space. If you've watched Night Shift Nurses or anything from that era of hospital-set adult anime and wanted something with an actual whodunit running underneath, this scratches that itch. Similarly, fans of Bible Black who appreciate when adult OVAs bother to have a real plot will find something here. It's short, it's from 1996, and it commits to both sides of its premise — the lecherous comedy and the genuine mystery — without fully abandoning either.