Mr. Gold asks David for help jogging Belle's memory; Anton's magic beans begin to grow; Rumpelstiltskin goes after a thief.

While Mary Margaret and David celebrate the naming of their son at a coronation in Granny's Diner, Emma and Hook are pulled into Zelena's time portal and find themselves in the Enchanted Forest of the past. But in their quest to discover a way back, they must be careful not to change anything or risk altering the lives of their friends and family - as well as their very own existence.

Hook and Emma try to find their way back to the present and correct the mistakes they made in the past.

A scared and confused Elsa from Arendelle finds herself in Storybrooke and creates a powerful snow monster for protection. Regina wonders if her relationship with Robin Hood has been completely quashed now that Marian's back in the picture. Elsa's sister wants to complete their parent's fateful journey and discover if their quest may have held the secret to containing Elsa's out of control ice powers.

Marian falls under a freezing curse and the townspeople believe that Elsa is responsible. When Emma and David go to Robin's camp to look for clues, they find Will Scarlet, who leads them to the culprit. Meanwhile, in the Arendelle of the past, Elsa and Kristoff go to find the urn that Hans plans to use to imprison Elsa, and encounter the Snow Queen.

The race is on to track down the elusive Snow Queen in order to discover what her ultimate end game is for Elsa and the residents of Storybrooke. Unaware that she does not possess the real blade that controls The Dark One, Belle attempts to use it to get her reluctant husband to show her where the Snow Queen is hiding. Belle travels to Arendelle and, with Anna's help, seeks out Grand Pabbie to help her regain her lost memories in order to discover the fate of her mother.

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.

Emma is still reeling after learning the truth of her parents’ history with Maleficent, but she must focus on finding the Author, who is running loose in Storybrooke, before Gold does. When Gold’s quest for his happy ending grows more urgent, he blackmails Regina into helping him. In a Fairy Tale Land flashback, Robin Hood learns what it means to be an honorable thief when he accepts a proposition by Rumpelstiltskin to travel to Oz to steal a valuable magic elixir from the Wicked Witch.

Emma’s potential for darkness is looming over everyone, but when Emma realizes Maleficent’s daughter Lily is in fact her closest friend from her foster care days, she resolves to find Lily and reunite her with her mother. Regina joins forces with Emma and together they set out to track down Lily and to warn Robin about Zelena. However, neither of them is prepared for the harsh realities they’ll encounter in the outside world. Meanwhile, in Storybrooke, Gold faces a crisis involving Belle. In a foster care flashback, things are looking up for young Emma with her new family until Lily’s appearance threatens to destabilize everything.