The Dragon Guard - The Magickers, #3

The Magickers are running out of time to master their abilities. No world is safe for Jason and his Magickers companions as the Dark Hand threatens to take everything away from them: their families, their Magick, and their lives.  Jason has escaped them once by the skin of his teeth-and opened a Gate to a world which might be their salvation, if only he could do it again. Jason might have found that elusive doorway except it has a very particular Guardian.
Can he convince that Dragon to aid his desperate quest or will Jason yet lose everything dear to him?