David - aka John Doe - must choose between staying with Kathryn or leaving her to be with Mary Margaret, with whom he's fallen deeply, and inexplicably, in love; and Emma catches Sheriff Graham in a lie.
Meanwhile, back in the fairytale world that was, Prince Charming is about to encounter a life-changing event that will forever alter his destiny.
Watch a sneak peek below.
ONCE UPON A TIME stars Ginnifer Goodwin as Snow White/Mary Margaret, Jennifer Morrison as Emma Swan, Robert Carlyle as Rumplestiltskin/Mr. Gold, Lana Parrilla as Evil Queen/Regina, Jared Gilmore as Henry Mills, Josh Dallas as Prince Charming/John Doe and Raphael Sbarge as Jiminy Cricket/Archie Hopper.
Guest starring are Jamie Dornan as Sheriff Graham, Anastasia Griffith as Kathryn/regal blonde, David Anders as Dr. Whale, Alex Zahara as Midas/nobleman, Alan Dale as King George, Ian Butcher as burly knight, Gabrielle Rose as Ruth/peasant woman, Demord Dann as aide, Matthew MacCaull as knight no. 1 and Robert Maillet as Behemoth.
"The Shepherd" was written by Andrew Chambliss & Ian Goldberg and directed by Victor Nelli.
Fans will be able to submit questions and receive real-time responses from actor Josh Dallas (Prince Charming/David), who will be up on Twitter at @joshdallas, during the East and West Coast broadcasts of the show.
DESPERATE HOUSEWIVES follows (9:00-10:01 p.m. ET) with an all-new episode, "Putting It Together."
Gaby, Susan and Lynette begin to panic when Chuck calls them in individually for questioning about the disappearance - and possible murder - of Alejandro. And Bree's life begins to spiral into despair when her friends abandon her after they blame her for scorning Chuck and causing him to take out his revenge on them.
Meanwhile, Lynette asks a favor of Tom that could ruin his relationship with Jane, and Susan is made a once-in-a-lifetime proposition to become a real artist.
DESPERATE HOUSEWIVES stars Teri Hatcher as Susan Mayer, Felicity Huffman as Lynette Scavo, Marcia Cross as Bree Hodge, Eva Longoria as Gabrielle Solis, Vanessa Williams as Renee Perry, Ricardo Antonio Chavira as Carlos Solis, Doug Savant as Tom Scavo, Jonathan Cake as Det. Chuck Vance, Charles Mesure as Ben Faulkner and Madison de la Garza as Juanita Solis, with Brenda Strong as Mary Alice Young and James Denton as Mike Delfino.
Guest starring are Kathryn Joosten as Mrs. McCluskey, Andrea Parker as Jane, Charles Carpenter as bartender, Shulie Cowen as Deirdre, Jessica Vilchis as Jill, Jennifer Cortese as Kelly, Leslie Jordan as Felix Bergman, Ruby Lewis as Chloe, Jeremy Rowley as nurse, Jeremy Luke as Jimmy, Cynthia Sophiea as mother, Joe Marinelli as father, J.J. Boone as administrator, Lou Richards as night manager and Jean Iavelli as Grandmother Manzani.
"Putting It Together" was written by Sheila Lawrence and directed by David Warren.
ABC's retro Sunday night soap, PAN AM, finishes the night (10:01-11:00 p.m.) with "Kiss Kiss Bang Bang."
Once in London, Ted enlists Laura's help to try to make an old flame - Amanda Mason (Ashley Greene) -- jealous, but things don't go the way he expects.
Meanwhile, Kate attempts to regain her freedom from her courier duties by agreeing to one last mission for her British contact, but the dangerous assignment not only puts her life in jeopardy but Anderson's as well; Maggie butts heads with a hawkish congressman who disagrees with her political views, but things really heat up when she tries to change his mind about his beliefs and ends up sparking an attraction with him; and back at home, Dean takes Colette to meet his parents and the two discover feelings that have been brewing for a long time.
PAN AM stars Christina Ricci as Maggie, Margot Robbie as Laura, Michael Mosley as Ted, Mike Vogel as Dean, Karine Vanasse as Colette and Kelli Garner as Kate.
Guest starring are Ashley Greene("The Twilight Saga: Breaking Dawn, Part 1," "The Twilight Saga: Eclipse," "The Twilight Saga: New Moon" and "Twilight") as Amanda Mason, David Harbour as Anderson, Chris Beetem as Chris Rawlings, John Bedford Lloyd as Captain Dennis, Damian Young as Mr. Bolger, Jim Coope as Bill Lowrey and Ann Dowd as Marjorie Lowrey.
"Kiss Kiss Bang Bang" was written by Moira Walley-Beckett & Lydia Woodward and directed by John Fortenberry.