The Vampire Diaries finally returns with a new episode this Thursday, April 7, and The CW doesn't want to alarm viewers. It's just... well...

EVERYTHING YOU KNOW IS ABOUT TO CHANGE.

So teases the latest, extended promo for "Know Thy Enemy," which also prepares fans for the final six episodes of season two. Based on snippets scene here, Jenna might find out the truth; Damon won't be wearing a shirt at one point; and everyone is preparing for the arrival of Klaus.

In a word: gulp.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.