Sammy gets braver and more daring with every book. This time she gets on a plane for Las Vegas without a plan and without a place to stay, in pursuit of her mother, who may be about to marry Sammy's boyfriend's father. (Sammy and her boyfriend happened WAY before the whole parents-dating thing, which is icky and uncomfortable, but at least not pseudo-incestuous.) She actually joins forces with her evil nemesis Heather Acosta, daughter of the putative groom, as they track their respective parents with the help of an army of Elvises, and the story ends with a showdown backstage at a rock concert at the House of Blues. It doesn't get more intense than that.
BUT...
...the thing I really cared about was that Sammy finally, FINALLY had it out with her mother about how irresponsible, selfish, and flaky she's been all these years. This is a showdown that was a long time coming and it was extremely satisfying. And we finally find out who Sammy's dad is and why Lady Lana never told her anything about him. (The reasoning is typical of Sammy's mother, i.e. flaky and indecisive.) I'm looking forward to the next book, where Sammy and her mom and dad start learning how to relate to each other as a family.