This is a clip from The Vampire Diaries episode "History Repeating." In it, Elena tells Stefan how Damon is "tormenting" Bonnie.
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Who is Emily? We'll find out on the Vampire Diaries episode "History Repeating." Watch this promo for it.
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The Vampire Diaries Season 1 Episode 9 Quotes

I'll adopt the Stefan diet, only nothing with feathers.

Damon

It does dead flesh good.

Damon [on coffee]