The Hunters (Brotherband Chronicles, #3)

Hal and his brotherband crew are hot on the trail of the pirate Zavac and they have one thing only on their minds: Stopping the bloodthirsty thief before he can do more damage. Of course, they also know Zavac has the Andomal, the priceless Skandian artifact stolen when the brotherband let down their guard. The chase leads down mighty rivers, terrifying rapids, to the lawless fortress of Ragusa. If Hal is to succeed, he will need to go beyond his brotherband training. He will need to challenge the pirate one-on-one, knowing only one of them will survive.