Frozen 2

King Agnarr of Arendelle tells his daughters Elsa and Anna that their grandfather, King Runeard, forged a treaty with the neighboring tribe of Northuldra by building a dam in their homeland, the Enchanted Forest. A fight occurred, resulting in Runeard's death and enraging the forest's classical elements of earth, fire, water, and air. The elements disappeared, and a wall of mist trapped everyone in the forest; Agnarr barely escaped, helped by an unknown savior.
Three years after her coronation, Elsa celebrates autumn in the kingdom with Anna, the snowman Olaf, the iceman Kristoff, and Kristoff's reindeer Sven. One night, Elsa hears a mysterious voice calling her. She follows it, unintentionally awakening the elemental spirits, who are forcing everyone in the kingdom to evacuate. The Rock Troll colony arrives, and Grand Pabbie tells the sisters they must set things right by uncovering the truth about the past. Elsa, Anna, Olaf, Kristoff and Sven follow the mysterious voice, and travel to the Enchanted Forest.
The mist parts at Elsa's touch, while the air spirit appears as a tornado, catching everyone in its vortex until Elsa stops it by turning the vortex into ice sculptures that show images from their father's past. Elsa also befriends the fire spirit, who is an agitated magical salamander. They later encounter the Northuldra and a troop of Arendellian soldiers who are still in conflict with one another. Anna and Elsa arrange a truce between the soldiers and the Northuldra after discovering that their mother, Queen Iduna, was a Northuldran who had saved the Arendellian Agnarr. The Northuldra tell them about a fifth spirit, who is meant to reunite the people with the magic of nature.
While Kristoff and Sven stay with the Northuldra, Elsa, Anna, and Olaf continue north. They find their parents' wrecked ship and a map with a route to Ahtohallan, a mythical river said to explain the past. Believing she should continue alone, Elsa sends Anna and Olaf to safety despite Anna's protests. She encounters and tames the Nøkk, the water spirit who guards the sea to Ahtohallan. Elsa discovers that the voice calling to her is the memory of young Iduna and that her powers are a gift from nature because of Iduna's selfless saving of Agnarr. Venturing into the most dangerous part of Ahtohallan, she learns that the dam was built as a ruse to reduce Northuldran resources because of Runeard's contempt for the tribe's connection with magic, and that he began the conflict by murdering the Northuldran leader in cold blood. Elsa relays this information to Anna before freezing solid, which in turn causes Olaf to fade away from existence.
Upon discovering the truth, Anna concludes that the dam must be destroyed for peace to be restored and the forest to be freed. She awakens the earth spirit, Jötunn, and lures it towards the dam. The massive rock giants hurl boulders, destroying the dam and sending a flood down the fjord towards the kingdom. Elsa thaws and rides the Nøkk to Arendelle, where she freezes the flood and saves the kingdom. As the mist disappears, she rejoins Anna and revives Olaf, before Kristoff proposes to Anna. Realizing she is the fifth spirit herself, Elsa explains to Anna that they are the bridge between the people and the magical spirits. Elsa abdicates the throne to Anna and becomes the protector of the Enchanted Forest, visiting Arendelle regularly with peace restored.
In a post-credits scene, Olaf visits Elsa's ice palace and recounts the events to Marshmallow, the snow giant created by Elsa as palace guard, and the Snowgies, miniature snowmen inadvertently generated by Elsa from sneezing.