Klaus takes Stefan to Chicago, where he wants to resuscitate his sister Rebekah, who might hold the key to breaking the curse. Gradually, Stefan is reminded of his Prohibition period affair with her while still bloodthirsty himself, and its tragic end. Tyler is rightly worried, turning for an ally to her mother sheriff Forbes, about the whereabouts of Caroline, whose bully father Bill actually holds her in a dungeon for 'vampire aversion therapy' of the most flagrant kind. Katherine puts Damon on feared Klaus's trail, so he can mount a rescue with Elena after putting her in her place.