Ariel returns to Storybrooke and pleads with Hook to help her find Prince Eric, who never returned to the town when the new curse was invoked. Emma agrees to let Regina teach her how to use magic so that she can help defeat Zelena, and Mary Margaret and David try to prove that they can be just as much fun as Hook is with Henry -- who thinks they are boring. Meanwhile, in Fairy Tale Land during the past year, an angry Ariel confronts Hook over her missing Prince Eric, who she assumes was kidnapped and possibly killed by the swarthy pirate. But when Hook confesses that the Jolly Roger has been stolen and Eric is most likely the thief’s prisoner, Ariel unknowingly provides him with a clue as to who the culprit is, and Hook – with Ariel in tow - goes off in search of his ship.

While Mary Margaret and David celebrate the naming of their son at a coronation in Granny's Diner, Emma and Hook are pulled into Zelena's time portal and find themselves in the Enchanted Forest of the past. But in their quest to discover a way back, they must be careful not to change anything or risk altering the lives of their friends and family - as well as their very own existence.

The Snow Queen attempts to pit Anna and Elsa against each other; with her powers out of control, Emma seeks assistance from Gold; Regina's quest takes a surprising turn.

The Author proves to be a formidable wild card and forges an alliance with Gold. Emma, 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

Gold and Belle convince Emma to help Gideon, explaining that together they can stop the Black Fairy. Henry experiences a disorienting shift in his powers that forces Regina to seek counsel from the previous Author. Meanwhile, in Fairy Tale Land, Hook attempts to win the assistance of an old adversary by betting his most prized possession on a game of cards. And, in a flashback, the Black Fairy tortures young Gideon in hopes of molding him into the perfect apprentice.

Henry grapples with an important decision when a job prospect in New York threatens to take him away from Jacinda and Lucy, but a revelation in the case of The Candy Killer could make it even harder to leave Hyperion Heights. Meanwhile, Margot confides in Tilly, and in a flashback, Hook helps Henry find a way to prove himself to Ella.