Ranmaru is a shy, dorky guy with a tongue that can analyze any element simply by licking an object, a skill that allows him to solve all manner of crimes. With his cute, but annoying sidekick Hikaru, plus the steadying hand of friend Kanji, Ranmaru solves a series of strange events at a failing hot spring resort deep in the mountains. Ranmaru falls in love with a doctor who saves his life. The loveable, endearing Ranmaru and his band of quirky pals team up to solve a nasty murder mystery that devastates the village.