To me, this felt like half a book. I like short books very much - I bought this because it was short - but I expect them to have a beginning, a middle and an end. This book had a beginning and an end, but introduced a whole lot of stuff in the middle which was never resolved.
I understand the book is part of a series, but it didn't end in a way which left you thinking the unsolved things would ever be continued. I imagine they would be, but why write a 100 page book when you have material for 200 pages? Why stop it at 100 pages when you have introduced a mystery, then just abruptly leave it? It was weird. I didn't hate the book - my displeasure is more because I enjoyed it, and wanted the mystery solved. I wanted more time with Hal and Cassie, see if Cassie had anything to do with the mystery. It just seemed like we'd never see those characters again, and never find out.
But the good parts - I thought Cassie was a great character, I could really feel her emotions and I liked her a lot. And Hal - he was very, very, VERY nice. He sounded gorgeous and he was strong and manly without being a dominating prick. I hate that a "strong" man in today's writing equals possessive jerk. Hal was kind and sweet and lovely but every inch a strong man, emotionally and physically, and I loved him. He was wonderful. I wanted more time with him and Cassie alone, after she found out who he really was. We never really saw them alone after that. I don't mean sex, exactly, but time together. I like them both so much.
If I knew for sure the mystery would be solved in the next two books, I'd read them. But if it's more intrigue without any resolution, I don't think I'd bother. The tale of the Dragon Kings wasn't told in a very smooth way, so that was kind of painful. But I'm glad I read this, because I met Hal. I have a sudden urge to visit Scotland :)