Elena and Alaric both lash out at John (recurring guest star DAVID ANDERS) when Isobel's (recurring guest star MIA KIRSHNER) unexpected arrival leaves Jenna devastated. Bonnie works with Damon and Jeremy to find the spell they'll need to harness her ancestors' power, and a heartbroken Caroline doesn't know what to do about Matt. Plus, Stefan and Damon realize they have a new secret weapon.