In the season premiere episode, "A Tale of Two Sisters," a scared and confused Elsa finds herself in Storybrooke and, fearful of the intentions of its residents, creates a powerful snow monster for protection. With Robin Hood's wife, Marian, back in the picture, Regina wonders if her "happily ever after" with the former thief has been completely quashed; while on their honeymoon, Mr. Gold finds an intriguing object that makes him question whether or not he should officially give Belle control over the dagger that makes him The Dark One, and Hook is dismayed to discover that Emma seems to be avoiding him while she tries to help comfort Regina after being the one responsible for bringing Marian back from the past and into Storybrooke. Meanwhile, in Arendelle of the past, as Elsa's sister Anna's wedding to Kristoff nears, Anna discovers that their parents - who died on-ship during a violent storm - were heading to a mysterious destination in a quest that may have held the secret to containing Elsa's out of control Ice powers. And against Elsa's wishes, Anna wants to finish their journey to find out what they were looking for.

When an icy spell is cast on Marian, which will ultimately freeze her heart and kill her, the Storybrooke residents place the blame on Elsa. But unbeknownst to anyone, a mysterious woman who runs the town's ice cream parlor has the same powers as Elsa and is trying to frame her. Emma and David find former Merry Men member Will Scarlet rummaging through Robin Hood's tent, Regina teams up with Henry to try and discover who the author of the fairy tale book is, Mary Margaret is having trouble balancing her duties as leader of Storybrooke and mother to young Prince Neal, and Hook begins to suspect that Mr. Gold is still in control of the dagger that calls upon him to be the Dark One. Meanwhile, in Arendelle of the past, Elsa and Kristoff set off to stop Hans from attempting to take control of the kingdom.