On Once Upon a Time's special upcoming two-hour episode on Sunday, Nov. 15, Brave lass Merida (Amy Manson) will go on a quest with both Ruby (Meghan Ory) and Mulan (Jamie Chung). That's also when we'll learn that she and Mulan have a history. "In the present day, she goes back to ask Mulan for her help," Manson tells TVGuide.com. "You'll see it cut to flashback as to why and find out who introduced them and what Mulan has taught Merida through her life and especially with fighting, in that sense, how to become the warrior she is."

But before that, on this coming Sunday's episode, Merida is so desperate to find her baby brothers, who've been taken captive by the clans of DunBroch, that she takes extreme measures.

"She ends up kidnapping Belle (Emilie DeRavin) because she finds something that Belle can do that she thinks will be useful in the quest to get her brothers back," Manson explains."There's nothing malicious about it, but by the time Belle knows where she is, it's too late for her to go back, so that's when they have a couple really heart-to-heart scenes and Belle agrees to help Merida on her mission."

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That's at least better than what's in store for Belle in Storybrooke. As part of the Dark Swan's (Jennifer Morrison) plan to bring out Rumple's (Robert Carlyle) heroic side, she compels Merida to hunt down the person he values most: Belle. Manson says, "[Merida] doesn't know what went on in the other realm, so she doesn't know who Rumple is, who Belle is to Rumple or that it is Belle. To Merida, it's just a horrible thing to do to a person."

Check out the sneak peek below to see how Merida handles the deadly mission.

Once Upon a Time airs Sundays at 8/7c on ABC.

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