Regina deals with the repercussions of losing Robin after Emma brings his wife from the past, and turns to an friend for help. Meanwhile, a mysterious ice princess arrives in Storybrooke and unleashes chaos. In the past in the kingdom of Arendelle, Elsa and Anna discover that their parents were killed trying to find a cure for Elsa's condition, and Anna sets out to find the same cure.
Elsa traps Storybrooke within a wall of ice while trying to find Anna, but is unable to release them... and puts Emma's life in danger. Meanwhile, when the power goes out, the townspeople insist that Mary Margaret deal with the crisis. And in the past, Anna visits David and helps him learn how to fight so that he can defeat the dreaded warlord Bo Peep.
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.
To prepare for his first real date with Emma, Hook blackmails Gold into restoring his left hand. However, the pawnbroker warns that all magic comes with a price. Meanwhile, Will tries to steal a book from the library. In the Enchanted Forest of the past, Anna has no choice but to agree to do a favor for Rumplestiltskin return for knowledge of why her parents traveled to see the Dark One.