Emma Swan's world is turned upside down when the son she gave up 10 years ago knocks on her door. Holding a book of fairy tales he claims are real, he tells her that she is not only in the book but that she is the only hope of freeing a town called Storybrooke from an evil curse.
Gold and Regina play dirty politics and take opposite sides when Emma runs against Sidney for Sheriff, as flashbacks show Rumplestiltskin desperately try to find a way to save his son from being enlisted into war.
Emma tries to save two children from foster care by trying to find their birth father, as flashbacks show the Evil Queen coercing Hansel and Gretel into stealing an important artifact from a blind witch.
Regina's plan for Mary Margaret is thwarted following Kathryn's sudden re-appearance and Gold becomes wary of August, as flashbacks show what happened to Baelfire after Rumplestiltskin became the Dark One.
Mary Margaret, Emma, Mulan and Aurora return to their camp only to find everyone dead. Back in Storybrooke, Regina begins to see a ghost from her past, as flashbacks show her training with Rumplestiltskin.
When a murder occurs in Storybrooke on a full moon, Spencer tries to bring the town against David by implicating Ruby, as flashbacks show Red Riding Hood find a pack of wolves who adopt her into their family.
Cora does everything in her power to steal the compass and find a way to Storybrooke, while after Aurora is kidnapped, and to protect Henry from further danger, Mary Margaret and David try to communicate with each other in the Netherworld.
As Hook and Cora arrive in Storybrooke, Regina struggles to gain the trust of the town, as flashbacks show Snow and Charming disagree over how to handle Regina now that they have taken over the kingdom.
Emma is shocked when she learns the true identity of Gold's son, as flashbacks show when Rumplestiltskin was called to war. Back in Storybrooke, Regina, Cora and Hook search for Rumplestiltskin's dagger.
Mary Margaret is tempted by dark magic and David, Emma and Neal attempt to protect Gold from Regina and Cora, as flashbacks show a young Cora seek revenge against the royal family after they degrade her in public.
Tension runs high as Hook's ship sets sail for Neverland to rescue Henry, Neal travels to Rumplestiltskin's castle with Mulan, and Henry finds himself on the run from the Lost Boys after Greg and Tamara are ambushed.
Emma meets Peter Pan, who gives her a map that will reveal Henry's whereabouts as soon as she accepts her true identity, while flashbacks show the Evil Queen present Snow with an offer, which Charming does not want her to take.
Mary Margaret, Emma, David and Hook attempt to rescue Neal and Gold and Regina begrudgingly agree to work together to take down Pan, as flashbacks show Snow White help Ariel get acquainted with Prince Eric.
As Hook's ship returns to Storybrooke, a well-hidden Pan puts a new plan into motion, while flashbacks show Snow and Charming go in search of a mythical being that could stop the Evil Queen cold in her tracks.
Emma works with Regina to find out who took everyone's memories from the past year, as flashbacks show the Evil Queen and Robin Hood attempt to break into her castle, which has been overtaken by the Wicked Witch.
The residents of Storybrooke try to prevent Zelena from stealing Mary Margeret's newborn baby for use in her evil plan, as flashbacks show Glinda attempt to convince Zelena to fight her evil tendencies and join her as a protector of Oz.
When an icy spell is cast on Marian, the residents of Storybrooke place the blame on Elsa, unaware the mysterious woman who runs the town's ice cream parlor has the same powers as Elsa and is trying to frame her.
Emma becomes determined to discover the Snow Queen's plan after discovering she was once her foster mother and Belle searches for the Snow Queen's hideout, as flashbacks show her travel to Arendelle to discover the fate of her mother.
Emma captures the Snow Queen and interrogates her at the sheriff's station and Regina and Robin's relationship grows increasingly complex, as flashbacks detail information about the Snow Queen's life in Arendelle.
Gold interferes with the Snow Queen's plans for his own agenda, as flashbacks show the Snow Queen try to pit Elsa and Anna against each other. Emma turns to Gold for help getting her powers under control.
As the Spell of Shattered Sight approaches Storybrooke, Emma and Elsa search for Anna, Belle and the fairies work on an antidote, and Gold, with a reluctant Hook as his servant, works on an exit strategy.
In the aftermath of the Snow Queen's curse; Emma looks for a portal so Elsa, Anna and Kristoff can return to Arendelle, Regina makes a difficult choice, and Gold's quest for power reaches a dramatic conclusion.
Hook and Belle search for a way to release the fairies from the Sorcerer's hat, Emma, Regina and Henry continue to look for clues that could lead them to the Author, and Gold and Ursula enlist Cruella to join their cause, as flashbacks show their first meeting.
Regina and Henry turn to Marco and Pinocchio for help in their quest to find the Author. Emma worries that Mary Margaret and David are hiding something from her as they remain wary of Cruella and Ursula.
In order to infiltrate the Queens of Darkness as a spy, Regina has to prove that she is still a villain. Meanwhile, Hook asks Belle for an unusual favor, and Henry makes progress on his search for the Author.
Maleficent puts Storybrooke under a sleeping curse in an attempt to steal the page that the Author is trapped inside. Mary Margaret and David struggle with their guilt as flashbacks show them go to extreme lengths to protect their unborn child from darkness.
Regina's plans to head to New York to rescue Robin from Zelena are halted when Cruella kidnaps Henry, as flashbacks show her encounter the Author, who encourages her to stand up to her oppressive mother.
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.
A royal ball is held in Camelot, but a dark turn of events forces David and Robin to take action. Meanwhile, Regina's fortitude is tested as she tries to safeguard Emma; and back in Storybrooke, Hook attempts to bring Emma back to the light.
Emma and Regina devise a plan to free Merlin, but they lack a pivotal ingredient. Meanwhile, Mary Margaret and David seek an important dagger; Henry asks Violet to go on a date; and Merida attempts to carry out a covert mission Emma has assigned her.
A surprise visit from Hook's brother Liam may provide Hook and Emma with the tools they need to defeat Hades; and in flashbacks, the bond between the Jones Brothers is tested as their merchant ships head into a storm.
Belle turns to Rumplestiltskin with hope of finding a way to protect their child from Hades. However, they disagree over whether to use dark magic, as Belle forbids Rumplestiltskin from using his powers for evil.
In flashbacks, Ruby and Mulan find themselves in Oz, where they meet Dorothy. After the three witness Zelena's return to Oz, they look for a way to defeat her once and for all. However, Dorothy mysteriously disappears.
Now that Hades and Zelena have been reunited, Hades tells Zelena about his plan to leave the underworld forever and Cora reveals information from the past that will change the lives of Regina and Zelena forever.
Emma, David, Regina, Robin and Henry are finally back home in Storybrooke and reunited with Snow, but, unfortunately, they still have to contend with Hades, who continues to deceive Zelena as he lays out his plan to use the all-powerful Olympian Crystal to take over the town. The heroes desperately search for a way to defeat Hades while Hook does the same in the Underworld, looking for those missing storybook pages. Regina and Robin take a more direct approach, which culminates in an epic showdown that will leave our heroes forever changed.
When a mysterious man from the Land of Untold Stories arrives in Storybrooke, David and Snow work together with Regina to neutralize the threat. Belle seeks Hook's help finding a safe place to hide away from her husband, Mr. Gold. Elsewhere, the Evil Queen continues to try to win Zelena over to her side, while Emma resumes her therapy sessions with Archie and shares her terrifying vision of the future.
Ashley is intent on settling unfinished business with her step-family; Regina tries to bribe Mr. Hyde for information on how to beat the Evil Queen; David makes a deal with Gold for information about his father.
In a flashback, Aladdin helps Princess Jasmine recover a secret weapon that could release Jafar's hold on the Sultan and save the city; in Storybrooke, the evil queen tricks Hook and tries to divide the family.
Emma tries to convince Aladdin to work with Jasmine to help Agrabah, while Regina teams up with Mary Margaret and David to free Archie from Zelena. The Evil Queen sows suspicion between Henry and Hook, even as Mr. Gold reminds her of his most important lesson. Meanwhile, in the past, Hook finds himself kidnapped by the mysterious Captain Nemo and held captive inside his legendary submarine, the Nautilus.
Snow White and Charming need to give up their hearts if they want to save Storybrooke from the Evil Queen. A magical sapling is sought. Snow White tries to get away from the Woodcutter. David has plans to sell the family farm.
Emma and Regina work together and form a plan to trap the Evil Queen, while Snow White and David get used to life without each other. Henry anxiously prepares to take Violet to the school dance, but the Evil Queen has other plans. Meanwhile Zelena and Belle form an alliance and recruit Aladdin to steal a magical object from Mr. Gold that could protect Belle and her unborn child from him forever.
In the Enchanted Forest, Rumplestiltskin steals Jack and Jill's newborn child in order to contact a powerful fairy, while in Storybrooke he uses fast-aging magic to send a message to Belle regarding their son. Meanwhile, The Evil Queen attempts to kill Zelena to earn Gold's favor and Jasmine discovers a magical lamp.
The Evil Queen sends Emma back to the Enchanted Forest and Regina must remind her of who she is. Belle and Rumplestiltskin try to figure out where their son is and David makes a wish that comes with a price.
The Evil Queen uses Robin as bait in order to trap Regina into battle; Hook goes to Captain Nemo for advice so he can make things work with Emma; Enchanted Forest flashbacks include the Evil Queen's father trying to give her advice on how to be a better queen for the people while she's chasing Snow White.
In flashback, Snow makes a wish that causes everyone to burst into song, infuriating the Evil Queen. In Storybrooke, this wish comes back into play as Emma and Hook prepare for their wedding, and the Black Fairy announces her plans.
Henry awakens to a cursed Storybrooke and discovers Emma has been in the mental hospital, and the Black Fairy is the new mayor. Henry attempts to help Emma regain her memory while Gold tries to find out what has really happened to Belle. Meanwhile, Snow, Charming, Regina, Zelena and Hook are trapped in a crumbling Fairy Tale Land and desperately try to figure out a way to be reunited with Emma and Henry.
Henry and Ella follow Alice into Wonderland, where Henry discovers a surprising connection between Ella and this strange world; Jacinda reconnects with an old friend in order to regain custody of Lucy, straining her relationship with Henry.
Henry and Ella must act to protect Lucy and the others from Drizella's curse, and Regina is forced to make an unimaginable choice; Roni recruits Henry to search for her sister; Gothel earns Anastasia's trust.
On Tiana's coronation day, an confrontation with Facilier compels her to take a trip through the Bayou; Sabine reconnects with an old friend, putting her culinary dreams at risk; Rogers and Weaver investigate a Blind Witch.
Rogers works to clear Tilly in the death of the Blind Baker. Ivy tries to reconcile with Anastasia. Meanwhile, Samdi makes a revealing confession to Roni. In the faraway realm, Alice forges an unbreakable bond.
When the witch killer attacks, Ivy must risk what remains of her family; Roni questions her relationship with Samdi as Henry and Jacinda grow closer; Drizella must face an unthinkable challenge to join Gothel's Coven.