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.