The Vampire Diaries (2009–2017)
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Know Thy Enemy 

Jeremy is delighted to have Bonnie restored to her powers, yet worried when accompanying her and Damon to the house where a 100 witches were burned to gather enough power to undo the ... See full summary »


Wendey Stanzler


Kevin Williamson (developed for television by), Julie Plec (developed for television by) | 2 more credits »




Episode cast overview, first billed only:
Nina Dobrev ... Elena Gilbert / Katherine Pierce
Paul Wesley ... Stefan Salvatore
Ian Somerhalder ... Damon Salvatore
Steven R. McQueen ... Jeremy Gilbert
Sara Canning ... Jenna Sommers
Kat Graham ... Bonnie Bennett
Candice King ... Caroline Forbes (as Candice Accola)
Zach Roerig ... Matt Donovan
Michael Trevino ... Tyler Lockwood (credit only)
Matthew Davis ... Alaric Saltzman (as Matt Davis)
Mia Kirshner ... Isobel Flemming
David Anders ... John Gilbert
Marguerite MacIntyre ... Sheriff Liz Forbes
Bryton James ... Luka Martin
Gino Anthony Pesi ... Maddox


Jeremy is delighted to have Bonnie restored to her powers, yet worried when accompanying her and Damon to the house where a 100 witches were burned to gather enough power to undo the moonstone's curse. Elena's mother Isobel Flemming's return startles her and even Katherine, as turns out doing Klaus's bidding for a gruesome 'prize'. John Gilbert confesses more wrong choices, also at Jenna's expense, yet unlike furious Alaric, Elena ends up choosing to keep her father in her life. The Salvatore brothers piece together from the Gilbert diaries what they believe equals a secret weapon. Matt can't handle the vampire truth and gets Caroline to wipe his memory. Written by KGF Vissers

Plot Summary | Plot Synopsis

Plot Keywords:

ritual | fire | fight | kidnapping | fall | See All (5) »


TV-14 | See all certifications »






Release Date:

7 April 2011 (USA) See more »

Company Credits

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Technical Specs


Sound Mix:

Dolby Digital



Aspect Ratio:

1.78 : 1
See full technical specs »

Did You Know?


[All trivia items for this title are spoilers.] See more »


When Caroline is telling Stefan about Matt, Stefan tells her to compel him and asks if the vervaine is out of his system. Caroline says she slips it in his soda but didn't get to the night before so it should be out of his system. All other times it takes three days for the vervaine to leave someone's system. See more »


Katherine Pierce: [entering] Don't get quiet on my account. If you have a plan to combat the impending vampire doom, please do tell.
[Damon just raises his brows]
Katherine Pierce: Seriously. What is the plan to get us out of this mess, hmm? I delivered you a moonstone, a werewolf, and a dagger to lure and kill Klaus. And right now, all you've got is a moonstone. Or so you tell me.
Damon Salvatore: No, we have it.
Katherine Pierce: Where is it?
Damon Salvatore: [confidentially] It's in a very safe place.
Katherine Pierce: I've been honest with you. Time to return the favor.
Damon Salvatore: Let me be honest with you. ...
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Halfway Gone
Originally by Lifehouse
Performed by Piano Tribute Players
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User Reviews

Lies, Betrayals and a Surprise
3 November 2013 | by claudio_carvalhoSee all my reviews

After the arrival of Isobel, Jenna decides to leave Elena's house. Meanwhile Jeremy and Damon go with Bonnie to the house where Emily Bennet and one hundred witches have burnt to death to collect their power. Jeremy discovers that Bonnie has hidden the truth about the power she has acquired. Katherine steals the moonstone and Isobel abducts Alaric, betraying Elena, Damon and Stefan. Matt betrays Caroline with his mother. John finds that he has been lured by Isobel.

"Know Thy Enemy" is and episode with many lies, betrayals and a surprise in the end with the appearance of Klaus. Elena disappoints not getting rid off John when he offers the chance. My vote is seven.

Title (Brazil): "Know Thy Enemy"

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