STAGE TUBE: Sneak Peek - 'The Price of Gold' on ABC's ONCE UPON A TIME

On this Sunday's episode of ABC's ONCE UPON A TIME entitled,  "The Price of Gold", Emma tries to help a young pregnant woman escape from the clutches of Mr. Gold. Meanwhile, back in the fairytale world that was, Cinderella (Jessy Schram, "Falling Skies") makes a regrettable deal with Rumplestiltskin.

Master storytellers Edward Kitsis and Adam Horowitz ("Lost," "Tron: Legacy") invite everyone to brace themselves for a modern fairytale with thrilling twists and hints of darkness, brimming with wonder and filled with the magic of our most beloved stories.

And they lived happily ever after... or so everyone was led to believe. Emma Swan (Jennifer Morrison, "House") knows how to take care of herself. She's a 28-year-old bail bondsperson who's been on her own ever since she was abandoned as a baby. But when Henry (JarEd Gilmore, "Mad Men") -- the son she gave up years ago -- finds her, everything changes. Henry is now 10 years old and in desperate need of Emma's help. He believes that Emma actually comes from an alternate world, and that she's Snow White (Ginnifer Goodwin, "Big Love") and Prince Charming's (Josh Dallas) missing daughter. According to his book of fairytales, they sent her away to protect her from the Evil Queen's (Lana Parrilla) curse, which trapped the characters of fairytale world forever, frozen in time, and brought them into our modern world.

Of course Emma doesn't believe a word, but when she brings Henry back to Storybrooke, she finds herself drawn to this unusual boy and his strange New England town. Concerned for him, she decides to stay for a while, but she soon suspects that Storybrooke is more than it seems. It's a place where magic has been forgotten -- but is still powerfully close -- where fairytale characters are alive, even though they don't remember who they once were, and where the Evil Queen, known as Regina, is now Henry's foster mother.

In order to understand where the fairytale world's former inhabitants came from, and what ultimately led to the Evil Queen's wrath, you'll need a glimpse into their previous lives to learn their origins. But it might just turn everything you've ever believed about these characters upside-down.

Meanwhile, the epic battle for the future of all worlds is about to begin. For good to win, Emma will have to accept her destiny and fight like hell.

"Once Upon a Time" stars Ginnifer Goodwin as Snow White/Mary Margaret, Jennifer Morrison as Emma Swan, Robert Carlyle ("The Full Monty," "Trainspotting," "SGU Stargate Universe") as Rumplestiltskin/Mr. Gold, Lana Parrilla as Evil Queen/Regina, JarEd Gilmore as Henry, Josh Dallas as Prince Charming/David and Raphael Sbarge as Jiminy Cricket/Archie.

ONCE UPON A TIME airs Sundays at 8:00-9:00 p.m., ET on the ABC Television Network. 

To view a clip from the upcoming episode, click below!