In this third book of the magical 'Frog' adventure series, young teenager Chris Casey is again pulled through time and space into another dimension - to the tropical world of Tropal. But something else has come to this paradise. Something unwanted. Something evil. The darkness that is Lord Maelstrom has taken refuge in the depths of Black Mountain...The first of his abominable creations are sent out to capture and enslave the chameleon people of the forests, to drain them of their colour and turn Tropal into a dead, grey wasteland. He searches for the fabled Tree of Spells, which gives absolute power to the holder. Should it come into his possession, every dimension, every world in time and space shall be truly doomed. A Guardian arrives to help Chris who, now in his guise as the indomitable Frog, meets a new companion: Mystra, a girl with extraordinary powers. Frog's quest is to find the Tree of Spells and take it back into his own world for safekeeping. He has to unravel a series of clues, which takes him on a perilous journey of encounters with gravity-defying caves, water witches, a swamp of dead souls, the banished Horsemen of Tropal, snow bears and, finally, into the heart of Lord Maelstrom's lair. Can he reach the Tree of Spells first? Will the Magic of the Immortals be enough to save the boy in whose blood flows an unseen and ancient secret? Frog's sense of humour and loyalty is always present, but this time, will his courage desert him, and will Lord Maelstrom finally triumph? This children's book, aimed at those aged 7 and over, will appeal to fans of adventure, time travel and exploring other dimensions.