When Toby Malone and Daisy Evans seek shelter in a doorway during a hailstorm, they do not expect to be thrown through a Unicorn Gate into another dimension. Now, they are destined to join Gabriel Greenway, a guardian from the ancient Order of Lumen, on a quest to retrieve a bright jewel stolen from the frame of the great golden harp whose magic sustains the world of Lumenor. Pursued and threatened by Maxwell Delano's organisation which draws energy from an evil Dark Star, Toby, Daisy and Gabriel must embark on a dangerous quest to find the jewel before its power can be corrupted into shadow...