A new obsession. A plot to bring down Silas. And... GHOSTS!

These are just some of the storylines viewers can look forward to on the penultimate episode of The Vampire Diaries Season 4, as The CW has released the official synopsis for "The Walking Dead."

It airs on May 9 and here is a look at what you can expect:

As Graduation Day approaches, Caroline tries to distract Elena by focusing on simple tasks like sending out announcements, but Elena won't be swayed from her new obsession.

Sheriff Forbes calls Damon and Stefan to the hospital, where someone has been attacking patients. Still trying to force Katherine to help her, Bonnie refuses to give up on her plan to defeat Silas.

As a violent wind storm causes a power outage in Mystic Falls, ghosts suddenly appear - some with good intentions and some bent on revenge.

Meanwhile, The Vampire Diaries returns tonight with "Pictures of You." What will go down at the Mystic Falls prom? Visit TV Fanatic the moment the episode ends for my full review and check out a few teasers from the installment now.

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