1.Beautiful Liar

In an attempt to rid Mystic Falls of Klaus and his schemes Bonnie figures out a spell to send Klaus back in time without damaging the bloodlines. Caroline has to be the distraction yet again but when the spell goes wrong and instead of sending him back in time it turns him back into his 3 year old human self, Caroline has no other option but to take care of him until Bonnie can contact his only living siblings to help her undo the spell.