When a powerful witch named Dame Alice feels threatened by Challenger's science, she calls upon her two beautiful acolytes to help undo his power. In order to earn full witchhood, the two must lure Challenger's "guards" - Roxton and Malone - to the witch's castle while she goes head to head with the "wizard" - Challenger - herself. While the two young witches distract Roxton and Malone, Dame Alice visits the Tree house for a visit. In spite of Marguerite's protests and warnings, Challenger is intrigued by the witch's power and too easily lowers his guard. When Dame Alice sabotages Challenger's newest invention and almost kills him, it is only Marguerite's quick thinking that saves the scientist from his own folly. But in the end it is not Challenger's life that is in danger, but the lives of Roxton and Malone.