Naniwa Shounen Tanteidan Episode 12

The parents and teachers are angry at Shinobu for bringing her students into danger while waiting for them to come back. In the end, Shinobu can catch the culprit after a "dramatic" scene in an empty house and bring back her students safely. They celebrate their very own graduatiion ceremony for her class and sensei realizes that it's hard to let the kids go. She refuses the detective's proposal as she planns on leaving the town to teach in a school in a very small village in Nagano.