EMMA AND MARY MARGARET, WITH MULAN, AURORA AND LANCELOT'S HELP, TRY TO FIND A PORTAL BACK TO STORYBROOKE, AND KING GEORGE POISONS SNOW WHITE, ON ABC'S "ONCE UPON A TIME"

Barbara Hershey Guest Stars as Cora

Sebastian Stan ("Gossip Girl," "Captain America: The First Avenger") Guest Stars as Jefferson

Sarah Bolger ("The Tudors") Guest Stars as Aurora

Jamie Chung ("Sucker Punch," "The Hangover Part II") Guest Stars as Mulan

Sinqua Walls ("The Secret Life of the American Teenager," "Teen Wolf") Guest Stars as Lancelot

"Lady of the Lake" - Emma and Mary Margaret, with the aid of Mulan, Aurora and brave knight Lancelot, attempt to find a portal that will bring them back to Storybrooke. But a dark force threatens their safe return. And Henry tries to talk Jefferson into reuniting with his daughter. Meanwhile, back in the fairytale land that was, on the eve of meeting Prince Charming's mother, King George poisons Snow White, and the only antidote lies within the waters of the Lady of the Lake, on "Once Upon a Time," SUNDAY, JANUARY 27 (8:00-9:00 p.m., ET) on ABC. (Rebroadcast. OAD: 10/14/12)

"Once Upon a Time" stars Ginnifer Goodwin as Snow White/Mary Margaret, Jennifer Morrison as Emma Swan, Lana Parrilla as Evil Queen/Regina, Josh Dallas as Prince Charming/David, Emilie de Ravin as Belle, Jared S. Gilmore as Henry Mills, Meghan Ory as Red Riding Hood/Ruby, and Robert Carlyle as Rumplestiltskin/Mr. Gold.

Guest starring are Barbara Hershey as Cora, Alan Dale as King George, Sarah Bolger as Aurora, Jamie Chung as Mulan, Sebastian Stan as Jefferson, Gabrielle Rose as Ruth, Sinqua Walls as Lancelot and Alissa Skovbye as Paige.

"Lady of the Lake" was written by Andrew Chambliss & Ian Goldberg and directed by Milan Cheylov.

"Once Upon a Time" is broadcast in 720 Progressive (720P), ABC's selected HDTV format with a 5.1 channel surround sound. This program carries a TV-PG,V parental guideline.

For more information on "Once Upon a Time," visit ABC.com/Once