For some reason, Hell Valley was filled with water. The excessive water pressure broke the rock layer, causing heavy losses to the ghosts living in the underground world. Prince Alois dived into the bottom of Hell Lake to investigate and found that the source of the disaster came from the tears of half a witch's head. In order to bring the witch who threw the head to justice, Alois set out to the surface... source: movie.douban.com/googletranslate