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Know Thy Enemy

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Know Thy Enemy is the seventeenth episode of the second season of The Vampire Diaries and the thirty-ninth episode of the series overall.


HIDE IN PLAIN SIGHTElena and Alaric both lash out at John when Isobel’s unexpected arrival leaves Jenna devastated. Bonnie works with Damon and Jeremy to find the spell they’ll need to harness her ancestors’ power. A heartbroken Caroline doesn’t know what to do about Matt. Stefan and Damon realize they have a new secret weapon.    



Main Cast

Recurring Cast



  • Antagonist: Klaus
  • First appearance of Klaus, though only while possessing Alaric's body.
  • Hilariously, Damon is revealed to have a closet full of black leather jackets.
  • Isobel dies in this episode, making her the second character whose name is also an episode title to die, after Rose.
  • This is the first time we see a lapis lazuli daylight ring be temporarily deactivated by magic.
  • This is the first episode to show a vampire being killed by sunlight exposure (Isobel).
  • This is also the first time that a character is possessed by the spirit of another living/undead person due to the use of a witch's spell.


Body Count

  • Isobel - Suicide/self-immolation in sunlight as a result of Klaus' compulsion.


Cultural References

  • "Know your enemy" is a saying derived from Sun Tzu's The Art of War.
  • "Know Thy Enemy" is a 2009 hip-hop drama movie.

Behind the Scenes

  • This episode had about 2.73 million viewers in USA, which was 0.26 million less than the previous episode.


Stefan: "Why don't you call Alaric and let him know that his wife just showed up on his girlfriend's doorstep?"

Damon: [to Katherine] "Don’t mistake the fact that we haven’t set you on fire in your sleep for trust."

Damon: [to Bonnie and Jeremy] "Great, we’ll have to put that on our list of things to do today-- harness dead witch power."

Elena: "You screw up everything, John. Everything you touch just falls apart. But, you’re the only parent I have left. So, maybe I can learn not to hate you."

Klaus [in Alaric's body]: Bulgarian: "Здравей, Катерина! / Zdravei, Katerina!" English: "Hello, Katherine!"

Elena [about Isobel]: "If that’s what you thought of her, then why did you ever put your trust in her at all?"
John: "Because I was there when she gave birth to you, Elena. I saw how heartbroken she was to give you up. And, because she was the first girl I ever loved. And, when she said she’d help keep you safe, I believed her."

John [about Isobel]: "I always knew that she and Katherine were close, but I never realized that Isobel and her were working against me. Two of the world’s most uncaring and selfish vampires, and yet they were genuinely friends."

Caroline [about Matt to Elena]: "You know, this wasn’t how it was supposed to happen. I was supposed to tell him at the right moment, in the right way, and he was supposed to be okay with it because he loves me."



Last.fm_play.png "Give Me Strength" – Snow Patrol
Last.fm_play.png "Halfway Gone" – Piano Tribute Players



See also

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