Truesilver: The Last Werewolf Hunter, Book 4

Zach looks forward to a quiet summer after finishing off the werewolf curse for good, so when Jolie and her cousin Matthieu ask him to help with waking up the sleeping ex-wolves in the store room, he thinks nothing of it at first. They're not dangerous anymore, right? But Zach soon discovers that some people don't need a werewolf curse to make them do evil things. Zach, Jolie, Cameron, and Matthieu quickly find themselves locked in a fierce battle with an accidentally-awakened sorcerer who is also a brilliant scientist. Only this time, they have nothing to fight him with.