The Ra-Seru heroes discover that the Genesis Trees of Buma are frozen and try as they might they cannot revive them with the Ra-Seru powers. Once they travel to Usha Research Center, they find out from Dr. Usha that the cold air that froze Buma and the Genesis Trees comes from an Ice Seru called Koru, which resides in Nivora Ravine. However, they cannot merely attack Koru, as it has been storing heat in its body for many years and a wrong move could cause it to explode, incinerating them as well as half of Karisto Kingdom with the blast.