Abby and Spike are drawn into a world of witches, hidden caverns, fabulous boats, captive children, lost parents, and a quest to find Ice Dust - the source of magical power. With their strange new companions - Captain Starlight, Benbow the giant albatross, and Sir Chadwick Street, flamboyant Master of the Light Witches - they hurtle through perilous seas, face fearsome monsters, and do battle with an enemy darker and dirtier than they could ever have imagined.