is the 23rd episode and second half of the two-hour Season 4 finale of Once Upon a Time , which originally aired on May 10, 2015. The episode concludes the "Heroes and Villains" arc, following Henry’s quest to restore reality after the Author, Isaac Heller, rewrote the lives of the residents of Storybrooke into a "Bizarro" Enchanted Forest where villains win and heroes lose. Plot Summary
Upon returning to Storybrooke, the characters face immediate new threats: [S4E23] Operation Mongoose (2)
: The freed darkness attempts to possess Regina. To protect her friend’s hard-earned happy ending, Emma Swan sacrifices herself by tethering her soul to the darkness. She vanishes, leaving behind the Dark One's dagger, which now bears her name. is the 23rd episode and second half of
: Because Isaac broke the Author's code by writing himself a happy ending, he loses his powers. Henry is chosen as the new Author and uses Regina's "Light Savior" blood as ink to restore the world to its original state. The Storybrooke Aftermath To protect her friend’s hard-earned happy ending, Emma
: Before dying from the darkness's attack, the Apprentice reveals that only the Sorcerer, Merlin , has the power to destroy the darkness forever, setting the stage for Season 5. Key Revelations & Details Once Upon a Time season 4 finale recap: Operation Mongoose
: During a confrontation at the church, Regina chooses to save Henry from a fatal blow by Rumplestiltskin, proving her growth as a hero even in a world where she has no memory of him.