Erin Hunter 
Survivors: The Gathering Darkness #3: Into the Shadows 

Darkness threatens the Wild Pack in this epic third book in the second Survivors series! From Erin Hunter, #1 nationally bestselling author of Warriors, Survivors is full of wild and wonderful adventure (Kirkus Reviews, starred review) that will thrill fans of Spirit Animals and Wings of Fire.Storm is determined to protect her Pack from any threatbut how can she protect it from her own Packmates? Some dog is sabotaging the Pack from within, and suspicion and distrust are tearing the dogs apart. If they dont uncover the traitor soon, there will be nothing left for Storm to protect…