The Icebound Land by John Flanagan
Will and Evanlyn have been captured by the Skandians and taken north. Halt arrived just in time to see they sailing away. Vowing to rescue them, he went to get help. He is determined to do anything to save his apprentice and the king's daughter.
Will and Evanlyn soon find the Erak, the Skandian Jarl that took them, is rough, but sympathetic. But when they reach the village, things get more complicated. They hear that the Oberjarl has taken an unbreakable oath against Evanlyn's family. Can she keep her identity a secret long enough to escape?
Meanwhile, Halt and Horace travel northward to find their friends, battling knights on their way. but one ruthless knight proves to be more than they expected. Can they escape his fortress in time to save Will and Evanlyn from certain death?
**Book 3 in Ranger's Apprentice**
Previous book: The Burning Bridge
Next book: The Battle for Skandia