
As they play, Elsa loses control and she accidentally hits Anna with an explosion of ice magic. Anna is seriously injured. His parents went to the ancient mountains looking for help. A wise old troll told them that Anna could be saved – she was lucky to be hit in the head and not in the heart. As the years passed, Anna forgot about that night.
In order to keep Elsa a secret from others, their parents surrounded the castle with walls and never let anyone in. But whenever Elsa has strong feelings, the magic appears and is hard to control. Elsa doesn't want to hurt her sister anymore, so she stops playing with Anna.
It made Anna very lonely. Even after their parents got lost in the stormy sea, the sisters did not spend time together.
Years later, it is time for Elsa to become queen of Arendelle. For the day, the castle gates were opened. Hundreds of people attended the coronation ceremony. Elsa works hard to hide her feelings and powers.
At the party, Anna dances with the handsome Prince Hans of the Southern Isles. He made his heart beat. It seemed like they had all in common, so they decided to get married.
Elsa thinks their engagement is a bad idea. Anna could not believe it and started to argue. Elsa began to lose control and as she shouted, ice shot out of her hands. Everyone looked at Elsa in shock. Now all Arendelle knows is Elsa's secret. He panicked and fled to the mountains.
Anna felt terrible. Elsa's power has created a terrible winter storm in the middle of summer. He leaves Hans in charge of the kingdom and runs after Elsa. As Anna drove through the strong wind, her horse threw her into the snow and ran back to Arendelle.
Fortunately, he meets an ice harvester named Kristoff and his reindeer, Sven. Together they set out to find Elsa. As they climb the mountain, Anna and Kristoff discover the beautiful winter wonderland.
They meet a magical snowman named Olaf. Olaf knows where Elsa is and wants to help them bring back the summer.
Meanwhile, Hans is helping Arendelle's people. When Anna's horse returned to the castle without her, Hans turned to the crowd and asked for volunteers.
Returning to the mountain, Olaf takes Anna and Kristoff to a giant ice palace that Elsa created with her powers. Kristoff was impressed. Inside, Anna tells Elsa about a violent storm in Adrendelle. Elsa is worried and doesn't know how to melt the city, and she thinks Anna and Arendelle might be better off without her.
Anna wants Elsa home, but Elsa is too afraid that she will hurt more people. As they quarrel, a wave of ice magic explodes from Elsa's body and hits Anna's chest. Anna would not leave without her sister.
Elsa knows what she has to do. He uses his magic to make a giant snowman to drive Anna and her friends out of the palace.
Kristoff takes Anna to the troll. A troll tells them that unless Elsa's magic is reversed, Anna will freeze. Only the act of true love can melt a frozen heart.
Anna knows she loves Hans. When she starts shivering, Kristoff is worried about her. Hans and his soldiers have just arrived at the ice palace and attacked Elsa. They took him back to Arendelle and threw him into the dungeon.
When Anna arrives at Arendelle, she asks Hans to save her with a kiss. But Hans refuses because he only pretends to love Anna.
Hans wants to take over Arendelle by getting rid of Anna and Elsa. Hans left Anna alone and shivered. Olaf finds her and helps her warm up but Anna gets weaker.
Olaf glanced out the window and saw Kristoff running towards the castle.
Olaf thinks Kristoff is the one Anna needs to kiss.
At the same time Elsa had escaped from the basement, but Hans was behind her. Hans tells Elsa that his magic explosion hit Anna's heart.
Elsa was very sad, she fainted in the snow and closed her eyes. She felt everything she had done to protect her sister had failed.
Anna rushes towards Kristoff but just then she sees Hans has drawn his sword to kill Elsa.
Instead of saving herself, Anna jumps to protect Elsa from Hans' sword. Hans swung his sword but it shattered as it struck Anna's frozen body.
Elsa hugged her sister. Suddenly, Anna began to melt and the two sisters embraced. When Olaf noticed them, he remembered what the wise old troll said, “True acts of love will melt a frozen heart.”
Anna's love for Elsa has saved both of them and the Kingdom. The two sisters are best friends again and summer has returned to Arendelle. Elsa even made Olaf into a small snow cloud so as not to melt. Elsa has a surprise for Anna, the castle gates are wide open. Now everything is as it should be.