THE VAMPIRE DIARIES Season 2 Episode 17 Know Thy Enemy Sneak Peek : HIDE IN PLAIN SIGHT — Elena (Nina Dobrev) and Alaric (Matt Davis) both lash out at John (guest star David Anders) when Isobel’s (guest star Mia Kirshner) unexpected arrival leaves Jenna (Sara Canning) devastated. Bonnie (Katerina Graham) works with Damon (Ian Somerhalder) and Jeremy (Steven R. McQueen) to find the spell they’ll need to harness her ancestors’ power. A heartbroken Caroline (Candice Accola) doesn’t know what to do about Matt (Zach Roerig). Stefan (Paul Wesley) and Damon realize they have a new secret weapon. Wendey Stanzler directed the episode written by Mike Daniels (#217).