Halos is about a twenty-year-old woman who is on the run away from home and ends up in a small town. While there, her car is stolen. There she meets several people who don't like her at first because of her view on life.
Now, the first problem is Kristen's lack of usual deep character background. It drops you in the middle of the story and forces you flow along with it.
But that's not even half the problem.
The main character is very shallow, having a strange obsession with halos. Whenever she sees a halo, she takes that as a sign from God to proceed. She's a very childish character in that aspect.
The other problem is the whole book in general. The plot is worn out: perfect male lead whom she doesn't like at first, dumb dramatic scene at the end, engagement, the whole nine yards. This book is a huge disappointment, especially since Kristen has wowed us with interesting plots and characters before.