The Maker's Metal 3: The Maker's Metal, Book 3 (Unabridged‪)‬

Having bested the Olympians and fought an Aesir Valkyrie to a standstill, David Montague must now contend with the greatest threat to humanity yet: the Frost Giants, the Jotuns.

To win, he must travel to Odin’s domain and somehow convince the Allfather to aid him. Whether he succeeds or not, David will be humanity’s first—and only—line of defense against the Frost Giants.