Lydia vanishes from the hospital after a disturbing hallucination, and is found naked in the woods two days later. Isaac, a tormented teen abused by his father, is attacked while working in his father's cemetery; Derek appears to save him. Jackson begins bleeding black blood and is told by Derek that his body is resisting the bite. Derek forces Scott to watch Gerard kill an innocent werewolf and declare that they will eliminate all werewolves to avenge his daughter Kate's death.