Book Four in The Mortal Instruments series.
I loved the first three books. There was such a long wait between books three and four that I forgot a lot of the plot happenings so it took me a while to get into it. That said, I still didn't like it as much. Jace being so vulnerable and his refusal to believe that Clary loves his was getting a bit annoying. I like Jace's combination of bad ass Shadowhunter and wounded soul, but enough already! I liked Simon's storyline, but couldn't (and still can't) remember anything about the Mark of Cain. The back of the book says it's going to be a movie--looking forward to that. I think my daughter would like it. Overall, the series is great. I will read anything written by Cassandra Clare.