The tower of bones - Frank P. Ryan

Four young people have slipped from our world into the enchanted land of Tr in this 'epic adventure that just does not stop!' (Glenda A. Bixler on Authorsden), where they must face a malicious demigod and an evil witch.

Alan, Kate, Mark and Mo could be an enormous force for good in this beautiful but war-torn, deeply oppressed world - but one of their number has been kidnapped and one lost, and one is changing almost beyond recognition. It's up to Alan to reunite them and restore their strength - but the Great Witch Olc, scheming in her Tower of Bones, has resurrected the malicious demigod Fangorath to use for her own evil ends, and she is planning to lure Alan into a trap.

Millions are depending on them, but they're not just fighting for one world any more . . .