Kaa-chan no Tomodachi ni Shikotteru Tokoro Mirareta. The Animation

When his mom's close friend Shiori takes him in, Naoki ends up in the care of a mature, warm woman who's always treated him well — a living situation that isn't unusual on its own. That setup alone isn't unusual. What makes things complicated is that Naoki has been carrying feelings for Shiori for a while, and one day she walks in on him at exactly the wrong moment. What follows is the kind of tension that's hard to walk back from. This 2020 OVA from Studio Seven is adapted from a visual novel, and that source material shows — there's actual character groundwork here before things escalate, which gives the dynamic between Naoki and Shiori more weight than you'd expect from a single-episode release. The animation handles expressions and atmosphere well, and the soundtrack does real work setting the mood rather than just filling silence. If you've watched Aneki no Kounai Kaikinbi or Okaa-san no Untenshu and appreciated when this genre takes a beat to establish the relationship before diving in, this one follows that same approach. It's not trying to be subtle about what it is, but it's put together with enough care that fans of Sotsugyou XX Densetsu would find the production quality familiar and solid. One episode, straightforward premise, executed cleanly.