Princess Elsa of Arendelle has magical powers of ice and snow. After she accidentally injures her younger sister Anna with her magic, their parents bring them to a colony of trolls led by Grand Pabbie. He heals Anna by taking away her memories of Elsa’s magic. The king and queen decide that until Elsa learns to control her powers, they will close the castle gates and isolate her. Years of isolation creates a rift between the sisters and, when they are adolescents, their parents are killed at sea.

On Elsa’s coronation day, the castle gates open to the public for the first time. Visiting dignitaries include the handsome Prince Hans of the Southern Isles. Hans proposes to Anna, but Elsa objects to the alliance and lashes out, accidentally revealing her powers to the terrified court. Accused of witchcraft by the scheming Duke of Weselton, Elsa flees to the North Mountain and feels free for the first time. She builds an ice palace and decides to live a hermit’s life, unaware that her magic has plunged Arendelle into an eternal winter.

Anna ventures out to find Elsa, leaving Hans in command. She meets an iceman named Kristoff and his reindeer, Sven, and convinces them to bring her to the North Mountain. On the way they meet Olaf, a living snowman created by Elsa’s magic. At the ice palace, Anna tells Elsa about what has become of Arendelle. Elsa’s fear makes her hit Anna with ice, accidentally freezing her heart. In desperation, Elsa creates a giant snow monster and casts Anna out of the castle to keep her safe.

With Anna slowly freezing to death, Kristoff takes her to the trolls for help. Grand Pabbie says that only “an act of true love” can thaw her heart. Kristoff races back to the castle so Hans can give Anna a true love’s kiss, but Hans captures Elsa. Instead of kissing Anna, he reveals that he has been plotting to become ruler of Arendelle by marrying Anna and then killing both sisters. The sisters escape and Olaf helps Anna reunite with Kristoff, whom he has deduced is in love with Anna.

Hans confronts Elsa, saying that she has killed Anna. Elsa breaks down, which abruptly stops the blizzard she created. Seeing Hans about to kill Elsa, Anna sacrifices her chance to be saved by Kristoff and steps between Elsa and Hans. She freezes solid, which devastates Elsa. As she hugs her sister, Anna slowly thaws; her heroism is “an act of true love”.

Realizing that love is the key to controlling her powers, Elsa ends the winter. Hans is arrested and exiled for treason and attempted assassination. Elsa appoints Kristoff the royal ice deliverer, and he and Anna share a kiss. The sisters mend their relationship, and Elsa promises never to lock the castle gates again.