Operation Mongoose Part 1

"Operation Mongoose Part 1" is the twenty-first episode of Season Four of ABC's Once Upon a Time. It was written by Edward Kitsis & Adam Horowitz, and directed by Romeo Tirone. It will be the eighty-seventh episode of the series overall, and will premiere on May 10, 2015.

This episode will be the first part of the season four finale.

Synopsis
The Author proves to be a formidable wild card and forges an alliance with Gold. Emma Swan, her parents, Hook and Regina scramble to stop them, but when Gold and the Author turn the tables on heroes and villains alike, the prospect of any happy outcome appears worlds away. Henry discovers he has big shoes to fill as he steps up to save his family before the story's final page is turned. It's a race to the finish, and everything culminates with a shocking twist that will leave the residents of Storybrooke reeling.

Starring

 * Ginnifer Goodwin as Snow White/Mary Margaret Blanchard
 * Jennifer Morrison as Emma Swan
 * Lana Parrilla as Evil Queen/Regina Mills
 * Josh Dallas as Prince Charming/David Nolan
 * Emilie de Ravin as Belle/Belle French
 * Colin O'Donoghue as Hook
 * Jared S. Gilmore as Henry Mills
 * Michael Socha as Will Scarlet/Will Scarlet
 * Robert Carlyle as Rumplestiltskin/Mr. Gold

Guest Starring

 * Lee Arenberg as Grumpy/Leroy
 * Kristin Bauer van Straten as Maleficent/Maleficent
 * Patrick Fischler as Isaac
 * Sean Maguire as Robin Hood/Robin Hood
 * Keegan Connor Tracy as Blue Fairy/Mother Superior
 * Timothy Webber as The Apprentice/The Apprentice
 * Michael Coleman as Happy/Happy
 * Paralee Cook as Wife
 * Faustino Di Bauda as Sleepy/Walter
 * David-Paul Grove as Doc/Doc
 * Jeffrey Kaiser as Dopey/Dopey
 * Gabe Khouth as Sneezy/Mr. Clark
 * Mig Macario as Bashful/Bashful