Get ready, Storybrooke...something wicked this way comes.
If the townspeople think Regina is evil, they'll quake in their boots should her mother, Cora, succeed in jumping over from Fairy Tale Land.
Cora in Storybrooke would be "terrifying," Jennifer Morrison told reporters on the Vancouver set of "Once Upon a Time."
"To me, she's the most terrifying villain we've had, only because she's so sweet and so charming and she's easy to believe."
"Cora makes Snow feel more unsafe than any other villain has thus far," added Ginnifer Goodwin. "When she smiles, she's actually more threatening."
In the winter finale, "Queen of Hearts," Cora and Hook continue to plot to steal the compass and open a portal to Storybrooke. Meanwhile, Emma and Snow head to Rumpelstiltskin's jail cell to get the ink that could trap Cora for good, then find their way back to their loved ones.
[Related: More TV spoilers and sneak peeks]
The race is on, but which side will triumph? See what the cast had to say about the big Dec. 2 finale.
Warning: Light spoilers ahead!
1. Regina grapples with her mother being alive.
"In Storybrooke, Regina thinks her mother's dead, to then learn that she's not. So what happened? (A). (B)…Oh no, she's coming to Storybrooke," Lana Parrilla said of her character.
"There's a lot of mixed emotions around that. Number one, she's terrified of her mother -- it's the worst possible outcome that could happen to her. [Cora will] just destroy everything and everyone. I think what she's most concerned about is losing Henry to Cora, because Cora always destroys the things she loves most: Her horse, her love, everyone."
2. Emma is the key.
Emma was the means of breaking the spell over Storybrooke, and her specialness will come into play again. When she and Snow are trapped, Emma is the one who figures out how to get out. And it involves magic!
3. Regina and Gold want to close the portal -- to everyone.
When it becomes clear that a passageway between the worlds is going to open up, the two will combine magical forces to close it. Unfortunately, that will mean Emma and Snow won't make it back home.
Of course, that would be "the perfect outcome for Regina if she could just close that portal," Parrilla noted.
David wouldn't be able to wake from the sleeping curse, while her nemeses Snow and Emma would be forever stuck in Fairy Tale Land. She'd have Henry all to herself again.
Henry would be "pissed off," Parrilla conceded, "but eventually would have to come and turn around. Who else do you have, kid?"
4. Henry will plead for his mother's and grandmother's lives.
While Emma and Snow getting trapped in Fairy Tale Land would be the best outcome for Regina, it wouldn't be for Henry.
"Henry's really glad he's having a much better relationship with Regina," Jared Gilmore said. "Of course, Emma is his biological mom, but Regina raised him and he does care for her and doesn't want her to get hurt. He is trying to help her change."
The question is: Will the changes stick?
5. Prepare to dangle over a very high cliff.
Will Emma and Snow find a way back to Storybrooke? Will Cora make it there instead?
All we can say is that there will be a huge cliffhanger at the end of the winter finale.
For fans, January will feel very far away.
Do you want to see Cora wreak havoc in Storybrooke? Sound off in the comments!
Watch a sneak peek clip from Sunday's episode and see how the Queen first met Hook:
"Once Upon a Time" airs Sunday, 12/2 at 8 PM on ABC.