Darkness Descending - Signed Book

He thought it was all over, that after a decade he was free to live his life as best he could with the knowledge he now possessed, but he always kept one eye upon the shadows, and for good reason, for danger had a habit of finding him, and it was about to do so once more.
 
The world had changed, but it needed them as much as ever, yet something was different this time, something was afoot which she kept hidden, and they all knew that spelt nothing but trouble.
 
Old and new foes sought to break them, plots and treachery seemed to be around every corner and once again they were the ones left trying to avert disaster. They didn't know how they kept getting themselves into these messes, but it was a safe bet that Lu would blame Morgan.
 
Can the boys decipher the clues in time, or will the end of their world happen at the cost of saving this one?
 
The final book in the trilogy and at 536 pages, it is a very large one. The book will also come signed by the author.