When Fire and Frost giants land on Earth, ancient Norwegian fairly tales of giants attacking and eating humans turn out to be all too real. The earlier Norse tales turn out to be of an advanced scouting expedition. Now, the main colony has landed near Death Valley.
A software developer, Olafson Daniel Oleson starts hearing and seeing things; a tall man with an eye-patch appears to him and asks him if he will make the ultimate sacrifice. Meanwhile, his Brother Tom, a Captain in the Marine Corps, fights a non-sanctioned battle near Death Valley against the oncoming horde of Fire and Frost giants.
Technology does not work around the Giants; electronics glitch out and the Fire Giants can make firearms spontaneously explode. The US has to get down to medieval weapons to fight the giants, and lose miserably.
Soon, O. Danny and Tom will learn what they need to do to become Odin and Thor, and take the battle back to the giants in the old manner.