Regina struggles to cope following Marian's arrival in Storybrooke, as a mysterious woman roams the town after emerging from Zelena's time portal.

Elsa accidentally places Emma's life in danger when she traps both of them inside an ice cave, as flashbacks show Anna help a younger Charming to fight a warlord named Bo Peep.

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.

Hook asks Gold for his hand to be reattached for a first date with Emma, as flashbacks show when Anna made a deal with Rumplestiltskin.

Regina reluctantly teams up with Emma to search for the Snow Queen after Sidney discovers her whereabouts, as flashbacks show a young Emma befriend a girl who, like her, is a runaway orphan.

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 everyone races to stop Emma from giving up her powers, Robin finds a clue that could point Regina to the elusive author of the storybook.

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.

As the Spell of Shattered Sight hits Storybrooke, Emma and Elsa race against the clock to free themselves of the ribbons and take down the Snow Queen.

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.

Hook tries to make a deal with Ursula as flashbacks show their complicated past, while Regina struggles to maintain her cover with Gold, Cruella and Maleficent.

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.

The Author joins forces with Gold and Regina fears for Robin's safety, as flashbacks show what happened to Robin after leaving Storybrooke with Marian and Roland.

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.

Emma realizes Maleficent's daughter is her former childhood friend Lily and leaves Storybrooke with Regina to find her, as well as to rescue Robin from Zelena.

Emma reunites Maleficent with Lily, who is still hell bent on seeking revenge against Mary Margaret and David. Meanwhile, Regina and Robin struggle to cope with the implications of Zelena's pregnancy.

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.

The author aligns with Gold, while Emma, her parents, Hook and Regina try to stop them; Henry steps up to save his family.