A keychain hunt doesn't sound like much until you realize this is just an excuse to watch Sasaki and Miyano exist in the same room without the weight of their actual feelings pressing down on everything. The episode moves at the speed of comfort, letting you hear how they talk to each other when neither one is terrified. It's filler, sure, but it's the kind that reminds you why you needed this series in the first place: to see two people who fit together actually fit, before the confession changes what that means.

Back from a field trip, Miyano and his friends are getting ready to take charge of the Discipline Committee. When a student misplaces a keychain, former chairman Hanzawa seizes the chance to set up the First Lost Item Detective Squad to track it down. Sasaki, still working out what his relationship with Miyano should become, joins the search hoping to be useful to him. Even with his help the hunt goes nowhere, and the squad soon learns that many other belongings have vanished too. The result is a single comedy and romance OVA with a slice-of-life feel, released with a special edition of the manga's ninth volume.