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.''