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Airing on September 28, the season four premiere of "Once Upon A Time" is the series' most highly anticipated yet. With the characters from Disney's smash hit "Frozen" set to invade Storybrooke, an overly-complicated third season makes way for possibly the sleekest and most interesting season since the series premiere.

However, even if you're not a "Frozen" fan (are scientists studying you?), there's still plenty going on with our OG residents of Storybrooke! We've seen the premiere, and here are five reasons why you absolutely need to be tuning in this season.

1. Queen Elsa Hasn't Quite "Let It Go":

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In the premiere, Elsa makes a discovery that shakes her to her core, totally stripping her of the control she once had over her powers. When she freezes Grumpy's car solid, the inhabitants of Storybrooke label her a threat -- and you know what happens when Elsa feels threatened.

As she battles her personal demons while trying to keep Anna safe at all costs, the kingdom of Arendelle is in jeopardy -- the evil Hans and his 12 older brothers still have their 26 eyeballs on Elsa's throne.

Fingers crossed for another show-stopping, award-winning song which will help Elsa find herself!

2. Things Get Awkward Between Robin Hood, Regina, And Marian:

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Emma was only trying to make things better when she allowed Maid Marian to go free at the end of the third season, but it rendered her already-tenuous relationship with Regina more fragile than ever.

Robin Hood makes his choice pretty early in the fourth season premiere, and let's just say that the woman he spurns does not take it well; his decision propels a huge story arc.

3. Villains Will Take Over:

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In ABC's extended sneak peek of the premiere, Regina laments the fact that she's "always the villain, even when [she's] not."

Judging by the premiere and by the fact that Kristin Bauer van Straten will return to "OUAT" in the latter half of the season to reprise her role as Maleficent for a "major arc," season four will definitely be the season of the villain.

However, villains are complicated, and none more so than Regina. Her motives this season will be rooted in self-interest, but it's not as black-and-white as saying that she'll be just "good" or "evil" as she continues on her personal journey. While you might have guessed that Sidney's return to the fold would not necessarily mean shiny, happy things, it's just not that simple anymore.

Also, let's not forget that Elsa has seemingly villainous tendencies herself -- for those who don't know her, the whole freezing-Storybrooke-over thing seems a bit hostile to its denizens. As we know, Elsa's intentions have always been pure as the driven snow, but this wouldn't be the first time she's been misunderstood. And isn't that how every villain is born?

4. Hook & Emma Are Still On Like Donkey Kong:

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While Hook and Emma will definitely be continuing their romantic relationship in some fashion, the course of true love never did run smooth. Emma begins the season feeling hella guilty for throwing a wrench into Regina's happy ending, and she's not really in the mood to flaunt her love for her eyelinered gentleman caller.

Also, let's be real -- Emma has always been scared of opening herself up and letting people in. She'll take any excuse, really, but Captain Swan shippers may enter the premiere with cautious optimism -- this feels like it will finally be the season where Emma throws caution to the wind!

5. The "Frozen" Characters Are Absolutely Delightful And Perfectly Cast:

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Speaking for myself, this is the only season where I've breathed so many sighs of relief over the real-life adaptations of our animated favorites. (Australian, blue-eyed Belle, my shade is forever reserved for you.)

Kristoff is more adorable than you could imagine, and anal retentive fans (me) will be glad to know that there is a perfectly good reason why he's not sporting the Jim Halpert-esque shaggy hair that he wore so well in "Frozen."

Sven is as well-spoken as ever, Grand Pabbie the Troll King is even rounder and wiser than we thought he'd be, and Anna is the awkward weirdo we know and love. Georgina Haig is also fantastic as a benevolent yet slightly insecure Queen Elsa who is still afraid of her own abilities.

BONUS: "Frozen" Isn't The Only New Disney Film To Enter The Mix:

For Disney diehards, this is the season for you. The "OUAT" premiere closes with a total game-changer, introducing an element from one of the most iconic films in Disney history! Can you guess what it is?

Tune in to the season four premiere of "Once Upon A Time" on Sunday, September 28 at 8 p.m., and check out the catch-up special at 7:00 p.m. if you're a bit behind. (We don't judge.) Let us know -- what are you most looking forward to this season?