The story itself was great. However, the narration left a bit to be desired. I'm not sure why Riordan felt the need to do it in the format of a audio tape transcript. He could have done it in a third person omnipresent style and it would have worked just as well, if not better. Not to mention, the little sister seemed like somewhat of a prat, like the kind you see in sitcoms. In sitcoms, they're a source of humor; however, this was a serious fantasy action drama, and stereotypical characters like that have no place in it. Despite that, I'm looking forward to the sequel, though I'm not sure when it will come out; it might even be out already.
