Winterborn 3: Shadow Blade by Stuart Grosse

Melinda Eriksdaughter and her adventuring companions were hired to uncover what was troubling the town of Moonwater. They thought it was just a few werewolves stalking the town at night. What they found was something even more disturbing than they could have imagined.A cult of werewolves dedicated to the Beastlord have invoked the Blood Moon, forcing werewolves in the Moonwood to remain in their changed shape, and driving them into a feral rage. But it is not the people of Moonwater that are the target of this cult. No, it is the temple dedicated to the moon goddess, site of a battle long ago.For the temple was sealed at the height of a battle years ago, cutting itself off from the outside world. Trapped inside are relics and artifacts of terrible power. Artifacts that could shake the balance of the world. But the seal is weakening, and almost broken.Now, their party must race against time in order to stop the werewolves before something terrible happens.