The book of Ga-Huel

"For centuries, Changlings have recorded the history of Trolls and Gumm-Gumms in The Book of Ga-Huel. This ancient tome is, literally, a living document with new entries mysteriously appearing--or disappearing--in it. When Trollhunter, Jim Lake, Jr., gains possession of the book, he and his friends are fascinated by what they discover. But when a new passage appears and it points to the death of a beloved friend, the team must race against time to uncover the invisible force predicting a future no one is willing to face"--Provided by publisher.