Derek Landy - Playing With Fire

She’s twelve. He’s dead. But together they’re going to save the world. Hopefully.The second book in the bestselling Skulduggery Pleasant series.Vengeous. Dusk. Sanguine. Three of the deadliest killers alive are in town to resurrect an unstoppable creature of horrifying power. And only Skulduggery and Valkyrie stand in their way.