When the story starts, Fimbulvetr, the unending winter, has arrived--three years have passed on earth with no spring. And Kathy Castillo, an MBA student, has been murdered, only to find her newly dead self offered a new life as a Valkyrie. Recruitment for Odin's army has been stepped up, and NorseCODE, a secret project funded by the Aesir gods, is tracking down every mortal descendant of Odin it can. Even ordinary ones like Kathy, now known as Mist.
But Mist goes AWOL. Instead of being a good Valkyrie, recruiting others, she decides that what's really important is finding her way to the kingdom of Hel, where most of the dead end up-- like Mist's sister, also murderd. To get to Hel and save her sister, Mist needs a guide, and the only choice is the Vanir god, Hermod, who made the journey himself once before (to save his own brother--it didn't work out). Hermod is a kind of loner god, not really into the mead-soaked fun and games of his family, and rather preoccupied with tracking down the wolves who are going to devour the sun and the moon....but off they go to Hel.
And then lots happens. Basically, Mist and Hermod team up to try to diffuse Ragnarok, despite all the weight of prophecy and immortal machinations pushing it forward to its deadly conclusion. They don't have much going for them--some help from Odin's eight-legged horse, and a bunch of dead farmers from Iowa (tornado victims) who, along with Mist's sister and the blind god Höd, have formed a resistance movement in Hel. Odin's all-seeing eye might help if they can get it, and then there's a sword partly forged from Nothing, that might be useful....
So there's a lot happening, and Mist and Hermod don't really know what the heck they are doing for much of the book, and even when they do know, they have a hard time being special enough to do it, and sometimes people die, and Ragnarok keeps on progressing--yet it wasn't depressing! I do not like depressing books, so this was good.
Reasons why it wasn't depressing, even though when the story begins it is never ending winter and it's all grim and one isn't at all sure if one wants to read it:
--Mist and Hermod manage to muddle through at every turn; they keep on trying, even when things look their darkest. This keeps the reader from losing hope too (I hate it when I lose hope).
--There are lots of little funny bits, little zingers that made me chuckle and longer bits of the author not taking things too seriously but not falling into farce.
--There is violence, and there's at least one graphic mentions of intestines, but it doesn't have the off putting pages of gore and fighting that one might encounter in grown-up books (and some middle grade fantasies)
--I liked the romance. If this were written as a YA book, there would be lots more about the romance, with angst and thrawtingnesses etc. This is a nice grown up romance, tastefully presented--growing tension, followed by brisk mutual enjoyment snatched from despair, conducted offstage. Though I wouldn't actually have minded a bit more conducted onstage.....
--I really liked the farmers from Iowa. Plain People of Middle America ftw!
--It is also not any longer than it needs to be. Clocking in at a brisk 292 pages, there was no wallowing in pointlessness.
In short, Norse Code is the best Ragnarok novelization I've ever read, and the best girl with bare shoulders holding a sword on the cover book I've ever (though it was my first, as far as I can remember, on both counts, so that isn't saying much), and, much more meaningfully, a cracking good read.
Note: I do not think you have to be deeply conversant with Norse mythology to appreciate it, but on the other hand, I think you need to have at least heard of Ragnarok and Odin's gang and Valkyries etc.
Additional note: Mist is from Mexico--her family immigrated when she was a child-- which is neither here nor there as far as the story goes, but there it is, so I'm counting this as multicultural fantasy, and anyone who has been wanting to read about a Hispanic Valkyrie need look no further.