Houtou Hides Something

The volunteer army leaves on its journey to save Kashin. To save her, they need to get three ingredients for the medicine. Kan'u goes to Koutou, Chou'un and Bachou go to Mt. Taishan, and Ryuubi, Chouhi, and Koumei go to visit Suikyou. The latter group arrives, but the ingredient they need isn't there...