Skulduggery Pleasant 1: Derek Landy

Meet the great Skulduggery Pleasant: wise-cracking detective, powerful magician, master of dirty tricks and burglary (in the name of the greater good, of course).
Oh yeah. And dead.
Then there`s his sidekick, Stephanie. She`s... well, she`s a twelve-year-old girl. With a pair like this on the case, evil had better watch out...
"So you won`t keep anything from me again?"
He put his hand to his chest. "Cross my heart and hope to die."
"Okay then. Though you don`t actually have a heart," she said.
"I know."
"And technically, you`ve already died."
"I know that too."
"Just so we`re clear."
Stephanie`s uncle Gordon is a writer of horror fiction. But when he dies and leaves her his estate, Stephanie learns that while he may have written horror, it certainly wasn`t fiction.
Pursued by evil forces intent on recovering a mysterious key, Stephanie finds help from an unusual source - the wisecracking skeleton of a dead wizard.
When all hell breaks loose, it`s lucky for Skulduggery that he`s already dead. Though he`s about to discover that being a skeleton doesn`t stop you from being tortured, if the torturer is determined enough. And if there`s anything Skulduggery hates, it`s torture... Will evil win the day? Will Stephanie and Skulduggery stop bickering long enough to stop it? One thing`s for sure: evil won`t know what`s hit it.