Elsa, princess of Arendelle, possesses the ability to. One night while playing, she accidentally injures her younger sister Anna. The king and queen seek help from,
who heal Anna and remove her memories of her sister's magic. The royal
couple decides to lock the family away in their castle until Elsa learns
to control her powers. Afraid of hurting her sister again, Elsa spends
most of her time alone in her room, causing a rift between the sisters
as they grow up. When the girls are teenagers, their parents are lost at
sea during a storm.
When Elsa comes of age, the kingdom prepares for her
Among the guests is the Duke of Weselton, a tradesman seeking to
exploit Arendelle for profit. Excited to be allowed out of the castle
again, Anna explores the town and meets Prince Hans of the Southern
Isles, and the two immediately develop a mutual attraction. Despite
Elsa's fear, her coronation goes off without incident. During the
reception, Hans proposes and Anna hastily accepts. However, Elsa refuses
to grant her blessing and forbids their sudden marriage. The two
sisters argue, culminating in Elsa's abilities being exposed to everyone
as she is unable to control her emotions.
Panicking, Elsa flees the palace, inadvertently unleashing eternal
winter on the kingdom in the process. High in the mountains far from
Arendelle, she casts off restraint, building herself a solitary ice
palace, and unknowingly brings to life her and Anna's childhood,
Olaf. Meanwhile, Anna sets out in search of her sister, determined to
return her to Arendelle, end the winter, and mend their relationship.
While getting supplies, she meets Kristoff and his Sven. She convinces him to guide her up the North Mountain. The group then encounters Olaf, who leads them to Elsa's hideaway.
Anna and Elsa are reunited, but Elsa still fears hurting her sister.
When Anna persists in persuading her older sister to return, Elsa
becomes agitated, and accidentally strikes Anna in the heart with her
powers. She then creates a giant snow creature to run the friends out of
her castle. As they flee, Kristoff notices that Anna's hair is turning
white, and seeks help from his adoptive family of trolls. They are told
that Anna's heart has been frozen, and unless it's thawed by an "act of
true love", she will become frozen solid forever. Believing that only
Hans can save her, Kristoff races back with her to Arendelle.
Meanwhile, Hans, who had gone on a search for Anna, encounters Elsa's
palace. In the ensuing battle against the Duke's men, she is knocked
unconscious and imprisoned back at the kingdom. There, Hans pleads with
her to undo the winter, but Elsa confesses she doesn't know how. When
Anna is reunited with Hans and begs him to kiss her to break the curse,
Hans refuses and reveals that his true intention in marrying her is to
seize control of Arendelle's throne. Leaving Anna to die, Hans charges
Elsa with treason for her younger sister's apparent death.
Elsa escapes and heads out into the blizzard on the fjord. Olaf finds
Anna and reveals Kristoff is in love with her. The two then rush onto
the fjord to find him. Hans confronts Elsa and tells her Anna is dead
because of her. In Elsa's despair, the storm suddenly stops, giving
Kristoff and Anna the chance to reach each other. However Anna, seeing
that Hans is about to kill Elsa, decides to throw herself between the
two and subsequently freezes solid, blocking the blow.
As Elsa grieves for her sister, Anna begins to thaw; her decision to
sacrifice herself to save her sister constitutes an "act of true love".
Realizing love is the key to controlling her powers, Elsa is able to
thaw the kingdom and even helps Olaf survive in summer. Hans is sent
back to the Southern Isles to face punishment for his crimes against the
royal family of Arendelle, and Elsa cuts off trade with Weselton. Anna
and Kristoff share a kiss, and the two sisters reconcile, with Elsa
promising never to shut the castle gates again.