As if their first, near-fatal altercation with him wasn't enough of an indicator, Frederick seeks vengeance on the Salvatores in next week's new episode of The Vampire Diaries.

This guy blames Stefan and Damon for his 145-year-old imprisonment in the tomb, and is a pretty bad ass vampire overall. So it's no shock that he makes a formidable foe.

But the perilous situation Stefan finds himself in, according to the promo below? Wow. With Stefan in grave danger, Damon and Elena turn to none other than Alaric for help.

That should be interesting, to say the least. Meanwhile, Matt is hopeful that mom Kelly will stick around, while Caroline makes a horrific discovery after her car breaks down.

Check out the promo below and tell us what you think ...

[video url="http://www.tvfanatic.com/videos/let-the-right-one-in-promo/" title="Let the Right One In Promo"] [/video]

Things aren't looking good for Stefan. Share your theories with us on what happens in "Let the Right One In," and click to enlarge some pictures from the episode below.

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Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.