It's time for our first costume party of The Vampire Diaries Season 7, fans! Caroline Forbes was set free from the Heretics house and now she's back in the game of planning epic dances!

Mary Louise and Nora are totally planning to crash it! (Seriously. With the rate at which things go terribly wrong at dances, you'd think they would all stop throwing them.)

We sat down with Teressa Liane, aka Mary Louise herself, to chat about what we can expect from The Vampire Diaries Season 7 Episode 4. Take a break from work and read on! (And then go watch The Vampire Diaries online so you're ready for tomorrow night's episode!)

TV Fanatic: What’s coming up for Mary Louise and Nora on this week’s episode?

Teressa Liane: We are going into this week and they're looking for Oscar, their brother. Basically, they know Damon has something to do with it. So they’re on a mission and they’re realizing that it’s not going to be something super easy. They lay out this ultimatum and it’s the two of them versus everyone else. We know they’re going to potentially kill people very soon if their brother doesn’t show up. They invite themselves to this Heaven and Hell ball that Caroline has organized. Whether she likes it or not, they’re going. We get to see them at this party and dealing with the challenges of Nora potentially flirting with other people and how Mary Louise reacts to that. There’s a lot of crazy tension coming up.

TVF: The costume parties on TVD are always just these fantastic events to watch, so how fun was it to film your first Whitmore College party?

TL: Oh, gosh, this was one of the most exciting things to film. Neil Reynolds, the writer, he created this awesome atmosphere and you could tell that the set design on the day was just amazing. We walked in and the lighting and everything had just been done to so much detail. The paintings on the walls had been altered to have devil horns and tails. I think some people even brought their own costumes and the costume department brought out some awesome, scary stuff. It’s going to be so much fun.

TVF: You mentioned Nora flirting around a bit at the party. Is this maybe a relationship that’s a little one-sided where Mary Louise is more dedicated than Nora is?

TL: I think they’re both incredibly dedicated, but Nora is more confident in it. She doesn’t feel the need to assert herself so strongly or the need to hold on to Mary Louise. She’s more confident in herself than Mary Louise is. The two of them are very devoted to each other and very much in love, but Mary Louise is very afraid of the two of them changing in this new world. But they’re very much in love and protective of their relationship.

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TVF: What was Mary Louise’s relationship like with Oscar?

TL: He was basically like a brother to her. All of them have these really funny individual personalities, so they all have this sibling, or close-knit friends sort of relationship. With him missing, she feels that and she’s definitely going to do all that she can to find him and get to the bottom of what has happened and where he is.

TVF: And of course it’s always Damon’s fault.

TL: [laughing] Yeah, it seems that way! They go about trying to find Oscar and yeah, they blame Damon. They’re very questioning of his motives and what he’s all about. So she and Nora go about finding Damon through Stefan so Stefan becomes attached by default to this mystery. These two brothers are not in good with Mary Louise.

TVF: Will we see that she finds out that it was actually Valerie who killed Oscar?

TL: At this point, they’re looking outward from the family. They don’t question that close circle.

TVF: We’ve seen bits and pieces of everyone’s history. Will we find out what brought Mary Louise to Lily?

TL: I’m not sure, but it’s something that I definitely hope for because I think they have a really great, amazing history, so yeah, I hope we get to see that.

The Vampire Diaries Season 7 Episode 4 Trailer

TVF: Is Mary Louise bothered by the fact that Lily let Caroline go?

TL: I think Mary Louise feels wronged by basically everyone at this point. She’s finding it really hard to know herself in this new world. She still loves and feels very loyal to Lily. If anything she’s just feeling really unsure of herself rather than placing the blame on other people, and in that way she’s acting out. It’s kind of a bully mentality where she’s going to hurt other people before she starts to hurt. In that rage and that violent streak, we’re going to see how a lot of this is coming out of her self-doubt.

TVF: What exposure has Mary Louise had to Julian? He seems to be the big bad who’s coming.

TL: Previously to them coming here, he was with Lily, so they saw him as a sort of step-dad. They’ve all had different experiences with him, and not everyone’s experience has been the same as Valerie’s. So, yeah, Mary Louise, she and Julian have a bit of a step-father, step-daughter relationship.

TVF: When we get into the history of these Heretics, we start to feel sad for them in a lot of ways.

TL: That’s what this show and these writers are so great at when it comes to villains. There are times when we hate them and there are times when they make us sort of love them. We want to know how they became these vengeful people. This show and its writers do a great job of giving us a window into how it happened and then letting the viewers make the decision of “okay do we sympathize or is there still no reason for them to go and kill all these people.” They did a great job with Valerie. That episode really got people to understand why she is the way she is.

TVF: We know Julian scares Valerie. What scares Mary Louise?

TL: I think losing Nora is her top fear. Anything else she’s willing to sort of fight for or against, but she hides this soft side of her with this acting out and this diva, mean girl behavior, but her deepest fear is not being loved and not having love in her life. This relationship she has with Nora is something so special and rare and she knows that and that’s why she protects it so strongly.