Wereing

Gruff fights the wereing to save himself and his human family

More than anything, Gruff would like to be the human boy that his new family thinks he is. But he knows he will always have to fight the wereing—the transformation into full werewolf—to protect them from the evil that lurks in the shadows.
 
But the werewolves aren’t just out to get Gruff—they plan to take over the entire town of Fox Hollow . . . and then move on to the next town, and the one after that, until they control the world. And these monsters have planned their first kill already—Gruff’s sister, Kim.