Regina does everything in her power to force Emma out of Storybrooke and out of her and Henry's lives forever. Meanwhile, the chilling circumstances of how the Evil Queen released the curse upon the fairytale world is revealed.

A dejected Sidney enlists the aid of Emma to help uncover evidence that could expose Mayor Regina as the corrupt person she really is to the townspeople of Storybrooke. Mary Margaret and David continue their secret rendezvous while trying to figure out a way to unleash their forbidden love. Meanwhile, back in the fairytale land that was, King Leopold, who is the father of Snow White and married to the Evil Queen, stumbles upon a magic lamp and is granted three wishes by a Genie - who warns the king to be careful what he wishes for.

While searching for a missing Mary Margaret, Emma is kidnapped by a man whose affinity for hats has him teetering on the edge of madness. Meanwhile, viewers will be transported outside of the fairytale land that was for the first time when the Evil Queen persuades a skillful man of magic to come work for her one last time and travel to Wonderland in order to help steal something from the Queen of Hearts.

Emma continues her exhaustive search for evidence that will prove Mary Margaret's innocence in the murder of David's wife, Kathryn. Meanwhile, in the fairytale land that was and before evil blackened her soul, Regina must choose between betraying her mother, Cora, and marrying for true love, or betrothing royalty and living a regal - but loveless - life; and the event that caused the Evil Queen to loathe Snow White is revealed.

Regina continues to seek a way to regain her powers; David continues his quest to find Mary Margaret and Emma; the seven dwarves discover what happens when one of the townspeople tries to leave Storybrooke's city limits.

When Regina is accused of murdering a beloved fairy-tale character, Emma thinks she is innocent; Prince Charming and Snow White plan the evil queen's execution.

The residents of Storybrooke race to stop Pan from placing another curse on the town.

Emma returns to Storybrooke to reunite Lily with Maleficent while Regina and Robin struggle to cope with the implications of Zelena's pregnancy. When Gold's health takes a turn for the worse, Isaac looks to a new ally for help procuring the magic ink he needs to re-write history. In a Fairy Tale Land flashback, Cora returns from Wonderland to beg Regina's forgiveness on the anniversary of Daniel's murder. Cora vows to help her daughter find true love, but Regina remains suspicious of her mother's intentions.

Emma, Regina, Mary Margaret, David, Robin, Henry and Gold arrive in the Underworld, on a mission to rescue Hook, only to discover that their search will be more difficult than they had anticipated. The inhabitants of the Underworld — all souls with unfinished business and many with quite personal vendettas — hound our heroes at every turn. Meanwhile, in an Enchanted Forest flashback, a familiar face from the Evil Queen’s past returns to present Regina with the perfect birthday gift.

Now that Hades and Zelena are reunited, Hades tells Zelena that he wants a future with her outside of the Underworld. All she needs to do is heal his heart with True Love’s Kiss so they can leave the Underworld and trap the heroes there for eternity. When Regina overhears of this plan, she enlists Cora’s help to find a way to separate Zelena from Hades. However, Cora reveals a family secret that could change Regina and Zelena’s lives forever. Meanwhile, David finally meets James, only to realize that his twin is determined to seek revenge on him for stealing the life he could have had.

Believing there isn't room in Storybrooke for both her and Regina, the Evil Queen sets out to eliminate her other half. Hook, determined to make things work with Emma, turns to his old friend Captain Nemo for advice, but Gideon torpedoes the plan before he's able to set things right.