In the aftermath of the Snow Queen’s spell, our heroes try to pick up the pieces and Regina has to make a difficult choice. Hook’s fate hangs in the balance as Gold’s quest for power threatens everything he holds dear. And, in the Enchanted Forest flashback, an intrusion during Belle's stay at Rumplestiltskin's dark castle will wreak havoc in both the past and the future.

With Gold banished from town, the residents of Storybrooke attempt to resume their normal lives. Hook and Belle search for a way to release the fairies from the Sorcerer’s hat, while Emma, Henry and Regina continue to look for clues that could lead them to the Author. But when a terrifying darkness descends on the town, Emma and Regina are forced to confront the true nature of evil. Meanwhile, in New York, Gold and Ursula enlist Cruella De Vil to join their cause.

David and Mary Margaret suspect Cruella and Ursula have come to Storybrooke looking for something more than their own happy endings – something that threatens to reveal a secret they thought was long buried. Emma begins her own investigation of Cruella and Ursula, but she can’t shake the feeling that her friends and family are keeping something from her. Regina and Henry continue their search for the Author, turning to Pinocchio and Marco in the hope Pinocchio might remember a clue that will help them. Meanwhile, in a flashback to Fairy Tale Land, Snow and Charming cross paths with the Queens of Darkness as the threat of the Evil Queen’s Dark Curse hangs over all of them.

In order to infiltrate the Queens of Darkness as a spy for the heroes, Regina must prove she’s still willing to get her hands dirty. Meanwhile, Emma, David and Mary Margaret scramble to keep tabs on their undercover operative. Hook requests an unusual favor from Belle as Henry makes progress on his search for the Author. In a Fairy Tale Land flashback, Regina befriends Maleficent and helps her to rekindle her lost spark.

Hook leverages his complicated history with Ursula to find out what she knows about Gold’s endgame. Gold and the Queens of Darkness torture August for information about the Author as Emma, Mary Margaret and David race to find them. Regina grows concerned for Robin Hood’s safety while she struggles to maintain her cover with the villains. In a Fairy Tale Land flashback, when a restless young Ursula enlists Hook’s help to run away from home, she soon learns it isn’t wise to trust a pirate.

Hook tells Emma that her fate is at stake in Gold’s plan while Regina leads the villains on a wild goose chase. Henry makes a breakthrough in his search to find the Author, but Mary Margaret and David need a moment to reconsider the best course of action. In a Fairy Tale Land flashback, Snow and Charming search for a way to ensure their child will grow-up to be a hero. When a traveling peddler directs them to visit a kindly old hermit, Snow and Charming are presented with a choice that could secure their child’s goodness, but at a price that will haunt them for years to come.

In fictional 1920s England, viewers meet a young Cruella, whose oppressive mother uses her Dalmatians to terrorize her daughter. Cruella is confined to her mother’s attic until a mysterious stranger arrives and empowers her to challenge her captor. In Storybrooke, Regina gains leverage to keep Gold from interfering with her plan to rescue Robin, but her trip to New York takes the backseat when she and Emma learn that Cruella has kidnapped Henry.

The heroes join forces with an old friend of Snow's to defeat an obstacle standing in the way of finding Hook. Meanwhile, Hook encounters challenges of his own.

Hook's captivity takes a dark turn when Hades threatens to condemn him to the River of Lost Souls after Hook refuses to choose which three of his friends will have to remain in the Underworld. Meanwhile, Gold is suddenly eager to help Emma, Snow, David, Regina, Robin and Henry find Hook so he can return home to Belle; but in order to do so, he must find his ex-wife Milah in the Underworld and ask for her help. In Fairy Tale Land flashbacks, Rumple and Milah face a life-or-death crisis concerning their son, Baelfire, that forces Rumple to make a deal that will haunt him.

In Underbrooke, Hook questions whether he is worthy of forgiveness after meeting his brother Liam. In the past, Liam makes a deal of his own to save himself and his brother... at the cost of a ship's worth of men. Meanwhile, Henry meets the Apprentice and learns of his true power.

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, and Ruby’s search for her new friend lands her in the Underworld. Reunited with the heroes, Ruby teams up with Emma, Regina and Snow to continue looking for Dorothy. Meanwhile, Snow and David struggle with not being able to be with their son, Neal, and devise a plan so that one of them can escape the Underworld.

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.

Hades turns to the heroes to ask for help with getting Zelena back from Rumplestiltskin and Peter Pan. In return, he offers to take all their names off their tombstones. However, when Hook is still unable to leave, he and Emma must journey into the depths of the Underworld. Meanwhile, Cruella De Vil is determined to keep the heroes trapped in the Underworld. In flashbacks, Emma searches for answers about her family and makes an unexpected friendship.

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.

As the residents of Hyperion Heights celebrate the breaking of the curse, Henry is visited by Wish Rumple, who’s hatched an evil plan to use Ella and Lucy to keep Weaver from destroying the Dark One powers. In order to stop him, Henry, Roni, Weaver and Rogers must travel to the Wish Realm, home to versions of some of our most beloved and fearsome characters. In a flashback, a discouraged Young Henry is visited by Wish Rumple and offered a deal that could have tragic consequences.