The Sea of Trolls (Sea of Trolls Trilogy Series #1)

Jack was eleven when the berserkers loomed out of the fog and nabbed him. "It seems that things are stirring across the water," the Bard had warned. "Ships are being built, swords are being forged."
"Is that bad?" Jack had asked, for his Saxon village had never before seen berserkers.
"Of course. People don't make ships and swords unless they intend to use them."
The year is A.D. 793. In the next months, Jack and his little sister, Lucy, are enslaved by Olaf One-Brow and his fierc…