The river flowing through the town suddenly gets dirty, and the demon beast, Edenoid appears from the water! Pollution spreads in a moment. RyuKenDo and RyuGunOu are fighting the demon, but it escapes too quickly and lost track. S.H.O.T's member, Rin Sakyo, burns hostility at the demon who soils clean water as an act that cannot be forgiven. Rin had memories of her late brother. With her brother trying to protect the river where fireflies can live, Rin headed towards the forest alone for the search where Edenoid is likely to be lurking.
