Gerda Hoffmann and her friends have only a few weeks left to unravel the mystery of the yew mirror. This ancient ritual is the only thing that can still prevent the witches from gaining more influence. However, the police's findings bring everyone the terrible realization that these matters are so old, so forgotten, and so incomprehensibly woven into our collective history that there are hardly any ways to understand them in time. As Walpurgis Night approaches, something palpably eerie is brewing over the Harz mountains, yet a solution seems out of reach. Thus, the women of the White Order set out on the morning of the last day of April, without having solved the riddle. They head to the old site of the sunken forest of dancing trees, to the Snake Mountain, the last known ritual site of the oak wise women. But they have no idea what they are supposed to do there.