Morgana Shee is a sorceress and sole guardian of the secret of the mirrors, the gateways to the parallel universe of the Wildworld, where legends come to life. But Morgana has been betrayed and imprisoned, while the evil sorcerer, Cadel Forge, threatens to escape from the Wildworld and conquer Earth.

Morgana's familiar, a magical fox, embarks on a rescue mission, seeking out four special children to help save her mistress. Armed only with courage and determination, the four siblings - Claudia, Alys, Charles and Jane - must find their way through the last surviving passageway to the Wildworld. But the crossing is only open for a single night during the Winter Solstice and time is running out ...