Patricia Jetton 
Werewolves Through the Portal [EPUB ebook] 

When a mythical werewolf falls into their trap, thirteen-year-olds Luna and Gizmo must find the portal to return him to his home. Once there, they discover a world of fantasy where mythical creatures really do exist and werewolves talk. However, things are not the way Discord the werewolf left them. His lifelong enemy has taken over his pack and has set new rules. His brother is locked in a cage, and the pack is starving. It’s up to Discord to defeat his enemy, free his brother, and take back his village. But that’s just the beginning of their adventures.