Ryohei Hachiya wants nothing more than to be famous, so he and his friends Sankichi and Shotaro devise a scheme: they'll investigate crimes around the city and interview potential witnesses and suspects, and turn over all of the evidence to the TV station! Along with three other girls from their elementary school, Keiko, Yoko and Yumiko, the trio will work towards Ryohei's dream of getting his ten minutes of fame.
Legends tell that while Japan was at war, the army stashed their treasure underground amidst Edo-era passages and war-time trenches. Ryuhei, Yoshio and Shun are chat room friends who decide to explore the underground and hunt down the treasure, and they have a good head start: Ryuhei found his father’s old secret notebook filled with detailed maps and hints! Along with Ryuhei’s little brother and the secretive ‘Mr. Acid Rain’, the children will scour the pipes and rat-infested tunnels of the underground in search for good fortune, meeting an eccentric cast of characters and an old war veteran along the way.