Finn and Erin Blackwell visit the quite Scottish hamlet of Ping during their summer holidays. They soon embark on an adventure that takes them into a different world, a world where Lethavian, The Dark Spirit, protected by the Purple Crystal, rules supreme.
Befriended by Willie and Cameron McDougal they embark on a quest to destroy Lethavian before he destroys them, and their world. Aided by Theodore, brother of The Dark Spirit they encounter a succession of dangers.
Their every move is watched through the eyes of large raven-like birds, Black Hammers, who feed their information to...