Fire Stone - Guardians of Glede: Next Generation, #4

Stranded after a river float trip goes horribly wrong, Brann van Tannen and his friends Tavin, Elek and Janna are caught by slave traders. To make matters worse, on board the barge are three trolls, descendants of the tribe that destroyed Mayfaire and killed Brann's grandfather. Brann will need to rely on all of the strength, wisdom and courage his father instilled in him while their lives are changed beyond wildest imagination.