Big Brothers — Mark A. Roeder

A new big brother is joining the family and Blue doesn't like him at all. He's perfectly happy with his current big brother, Colt, and does not want to share. Worse, Colt, Jacob and their new best friend, Malkon are keeping a secret from him, something called Tydannon. At first, Blue thinks it must be a fantasy game, but he slowly discovers Tydannon is a real place that exists in an entirely different world. Colt, Jacob and Malkon have been there. Blue's dads and his Great Uncle Skye have visited Tydannon as well. Why is his entire family keeping a secret from him? Blue is determined to discover the answer himself and seeks out Tydannon, only to discover he's trapped there and may never get home.