View the Anna Gallery.
Following the events of the film Frozen, Anna is preparing to wed Kristoff when Elsa finds a diary from their mother stating their real reason for their parents' fatal trip. Determined to seek answers, Anna postpones her wedding and travels to the Enchanted Forest (known as Misthaven in Arendelle). Anna meets David, a friend of Kristoff's, and trains him in swordsmanship so he can defend his farm from the evil warlord Bo Peep. Following Bo Peep's defeat, David gives Anna his horse and David's mother gives Anna the name of Rumplestiltskin, a powerful wizard who she believes can give her the answers she is looking for. Anna visits Rumplestiltskin (Robert Carlyle) who tells her that the King and Queen of Arendelle came to him, and he will tell her what they said if she administers a potion to an old man. Anna is afraid the potion is poison and pours it into the old man's fire. She returns to Rumplestiltskin's lair and lies, saying she has given the man the potion, and quickly learns it was an antidote, not a poison. In not giving him the drink, Anna has broken her deal with Rumplestiltskin and subjected the man to turn into a mouse. The deal, when broken, meant that Anna had to be Rumplestiltskin's slave—but, alas, Anna gets control of the dagger that controls him, and orders him to never harm her or her sister, and to send her back home with Rumplestiltskin's weapon, a magic-stealing hat. Back in Arendelle, Anna admits to Kristoff that Rumplestiltskin told her that her parents were afraid of Elsa. She does not tell this to Elsa, but is shocked to see that Elsa is learning to control her power—due to a new woman by the name of Ingrid (Elizabeth Mitchell), who claims she is their mother's sister and also has magic snow powers like her sister Elsa. Anna never knew their mother had a sister, so she is immediately skeptical. She goes to meet Grand Pabbie and the rock trolls to find out if this is the truth. While purchasing supplies at Oaken's shop, Anna runs into Belle (Emilie de Ravin) and they become friends. Together, they journey to the rock trolls, where Anna learns that her mother had two sisters named Ingrid and Helga, but Grand Pabbie changed everyone's memory in all of Arendelle. On the return journey back to the castle, Anna and Belle run into Ingrid. Ingrid sees that Anna has Rumplestiltskin's magic-stealing hat and believes she will betray her, so she grabs hold of Anna and imprisons her. Ingrid tells Anna that she has nothing in common with either her or Elsa as she has no magic as they, and now Ingrid must replace her. Eventually, Anna reunites with her sister, helps Ingrid see the errors of her ways, and marries Kristoff.
With the introduction of Frozen characters, the season 4 of Once Upon a Time saw a 31-percent increase in ratings from the autumn of 2013 (9.3 million viewers), marking its best ratings in almost two years.