Skulduggery Pleasant: Dark Days by Derek Landy

From chapters.ca:
What can we say, without giving too much away? Not much, is the answer. But what we CAN say is that this book is hilarious, it's tense, and it's packed with all the eye- popping action, crackling one liners and imaginative set pieces you've come to expect. There's a new threat to our plucky heroine, of course. But that's not all. There's also the little fact of the Big Bad, the uber- baddy who's going to come along and really, really destroy the world. (Really) And what we learn about that villain in this book will literally make your jaw fall off and your hair go white with shock. (Not really) Will Skulduggery make it out of the Faceless Ones' dimension? Who knows. The problem is, he may not have much to come back to...