Passage to Dawn: Legend of Drizzt: Legacy of the Drow, Book 4

Revenge and resurrection in a frozen wasteland! Drizzt and Catti-brie have been away from Mithral Hall for six long years, but the pain of a lost companion still weighs heavily on their strong shoulders. Chasing pirates aboard Captain Deudermont's Sea Sprite is enough to draw their attention away from their grief. Then a mysterious castaway on an uncharted island sends them back to the very source of their pain, and into the clutches of a demon with vengeance on his mind.