I'd rate this somewhere between "It's OK" and "I like it", so I'm rounding up to three stars.
The story was nice, but I could've done with a character to identify with. And without Helene's life story. I didn't feel that it contributed anything to the story. The ancient storyline at least set up some characters. I would even say I liked the Mesopotamian storyline the best. The other thing I liked is how the author takes a bunch of mythology and ties them all together in a neat bundle.