Jennifer Morrison is actively researching old fairy tales to prepare for her role as "Dark Emma" in season 5 of ABC's Once Upon a Time.

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Morrison recently spoke with People about the research she's been doing in order to properly get a hold on the new darker side of Emma. As fans watched, Emma was turned to the dark side in the season 4 finale of the fantasy series and it looks like she could be the new "Big Bad" of the series, at least for a while.

The actress said that she's been digging into some books from the New York Public Library to research how to play Dark Emma.

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"In order to build Dark Emma, I've been doing a bunch of research there with some of their mythology books and old fairy tale books and just looking back through the history of swans and the etymology of 'Swan,' " she explained.

"I was given the opportunity to go to the rare books department, and they showed me some of the most incredible first editions of old fairy tale compilations that were just stunning," Morrison added. "There were some stories in there that I'd never heard of, so I have yet to read them. I have a list of them that I'm working my way through now!"

Season 5 is ultimately going to be about Emma grappling with the darkness after spending so many years as the Savior, and how those around her will try to make her break free of that darkness.

"She's in a position where she is free of all of that and is facing all of the potential darkness that she has tried to avoid," Morrison said. "So we will see what that means for her, and we'll see how she grows and changes because of that," she says. "We're also going to see everyone in her life fighting to try to get her out of that place and help her overcome it."

Once Upon a Time season 5 is set to premiere on Sunday, Sept. 27 at 8 p.m. ET/PT on ABC.