Complex sentence: On Lydia's birthday, Peter manipulates her to drug all her party guests on full moon night and lure Derek to the old Hale House, where Peter uses his nephew Derek's Alpha werewolf blood to return to life from the underworld.
Split into simpler sentences: On Lydia's birthday, Peter manipulates her to drug all her party guests and lure Derek to the old Hale House on the night of a full moon. There, Peter uses his nephew Derek's Alpha werewolf blood to return to life from the underworld.