Kirsty and Angus are embarking on a family sailing trip around the world. What should have been the experience of a lifetime suddenly turns into a struggle for survival and escape when their parents disappear in a storm and their boat is shipwrecked. Marooned on the hidden island of Gruinsoye they discover a land full of mystery and menace, a cult of cloned psychics and gardeners(sowers)using ancient technology living side by side mythical beings the Storm Hags.

When Kirsty is found to have strong psychic powers she is captured by power hungry psychic Soyean and his hoard of genetically mutated Graks.

Angus joins forces with young sower Olaf and the Storm Hags. Together can they rescue Kirsty and save Gruinsoye from Soyean?