'Vampire Diaries,' '60s style?!: 10 Exclusive Pics!

When The CW's top-rated show returns April 7 from a six-week hiatus, it'll be ''all about the countdown to the arrival of Klaus (Joseph Morgan),'' executive producer Julie Plec says. As the high school prepares for its ''1960s Decade Dance'' in the April 14 episode, Elena starts receiving disturbing messages from Klaus (who wants to sacrifice her). She and those close to her expect him to attend the dance ? hence the episode title ''The Last Dance.'' ''Everything is tense for Elena because, of course, if Klaus is indeed coming for them and showing up, it's because of her. The reality is starting to sink in that this nebulous figure that she's only heard the lore about for the entire season is now proving to be a reality and she could be coming face-to-face with him at any moment,'' Plec says. ''While she's trying to put on a strong face for it, she's scared, and Stefan's scared for her. It's a big night for them.''

Because Klaus is expected to show at the dance, Damon and Alaric (Matt Davis) volunteer to serve as chaperones. ''They go in ready to take him out,'' Plec says. ''Yes, Damon and Elena share a dance,'' she adds. [EW giggles.] ''As fangirls across America sigh.'' Katherine does not attend the dance. Also interesting: Elena isn't wearing her vervain necklace. That's something that will be explained in the April 7 episode.

In the April 7 episode, Bonnie will have learned a lot about how she can help Elena, and what it will take. ''It's big,'' Plec says. ''By the time we get to the dance, the tension is really high between Bonnie and Jeremy because he's legitimately afraid for her life. Bonnie, as a witch, is one of the only weapons that our team has against Klaus. And for Jeremy, who's lost two girlfriends already in his life — in addition to his parents — it's really hard for him to watch Bonnie gear up for battle. He's gonna go through a lot emotionally out of concern and anxiety, and Bonnie's gonna go through a lot because she knows that she can help in this fight.''

''Poor Jeremy is just caught in the middle,'' executive producer Julie Plec says. ''Everything that Bonnie is willing to do is in the name of helping to save Elena from Klaus. But Jeremy has a vested interest in Bonnie's safety as well. He doesn't want to stop Bonnie from helping his sister, because he doesn't want his sister to get hurt, but he doesn't want his girlfriend to get hurt either.''

''As tends to happen in Mystic Falls, in spite of death and chaos and danger looming around every corner, Bonnie and Elena have had to get dressed up and go to the dance. And while they look very, very sassy in their microminis,'' Plec laughs, ''they are still very much aware of the danger that's there.''

Here Bonnie sits in front of a large television screen the show's production designer created as a backdrop for the dance. ''We cut together a montage of all the great images of the time,'' Plec says. Why a ''1960s Decade Dance''? Truthfully, the creators just thought it made sense since the school had a 1950s sock hop last season. ''Then we decided that maybe we were being too literal, but by that point, we realized that the '60s are actually a great decade because you still have the remains of the '50s influence and the great Jackie O. pillbox hat and wool Chanel, in the same era that you have psychedelic and funky and the beginning of hippie fashion. Wardrobe really went all out.''

When the show returns, Caroline has a problem on her hands with Matt (Zach Roerig), who's alive and well after she fed him her blood to save his life — but also traumatized to have learned his girlfriend is a vampire. ''She had this romanticized idea of how he would finally respond when she told him the truth about herself and it couldn't have gone more wrong. What is she gonna do about the fact that he knows the truth, and the fact that he doesn't seem to be able to handle it at all?'' Plec asks. She persuades him to escort her to the dance.

And if you haven't figured it out yet, they go as Jackie O. and JFK. ''It felt akin to her character, the idea of this powerful woman who had a great point of view and great style. Caroline, in her own mind, is always trying to live in some romanticized ideal of something, especially in her relationships. So it's the idea of representing Camelot and the wonderful couple of JFK and Jackie O., especially as she's trying to deal with the Matt problem,'' Plec says. Should we read anything into Matt dressing as JFK? ''You know, I saw that on the blogs, people saying, 'This does not portend a good future for him,''' Plec laughs. ''I can't say. But I wouldn't overthink it.''

Sheriff Forbes has been noticeably missing in action while actress Marguerite MacIntyre spent some time on crutches. ''We love our sheriff, we love the mayor, we love the Council, and this idea of the people in this town working behind the scenes against the vampires,'' Plec says. ''We weren't able to keep that story alive during that period [she was recovering]. It didn't hurt us at all. It just put pause on it.'' Now that she's back? ''There's a lot of stuff goin' down with her,'' Plec says. ''It's safe to say that things are gonna start heating up as far as what she knows is concerned.''

What would a ''1960s Decade Dance'' be without one?