While investigating two bizarre murders, Sam (Jared Padalecki) and Dean (Jensen Ackles) realize there is an eyewitness to both gruesome deaths - a German Sheppard. Anxious to find out if they are dealing with a witch, a skinwalker or other Supernatural monster, the guys look up a spell that could let Dean "communicate" with the dog. Unfortunately, the spell comes with side effects that no one saw coming.