Bloodsong (Paperback, Simon Pulse)

Fifteen-year-old Sigurd, son of King Sigmund, is the last surviving member of the Volson clan. His father's kingdom -- the former city of London -- is gone. And his father's knife, a gift from Odin himself, has been shattered to dust.

Now, Odin's eye is upon him. Armed with a powerful sword forged from theremnants of his father's knife, Sigurd will face death, fire, and torment. He must travel through Hel and back...to unite his country once again.