Kochira Katsushikaku Kameari Kouenmae Hashutsujo: Washi to Ore!? - Bokura wa Asakusa Shounen Tanteidan!

こちら葛飾区亀有公園前派出所ワシと俺!?〜ぼくらは浅草少年探偵団!〜

An amazing time machine invention allows Ryoutsu to return to the years of his childhood.