Frozen

Agnarr recounts Runeard's forged alliance with the Northuldra and the construction of a dam in the Enchanted Forest. The ensuing conflict costs Runeard his life and triggers the forest's elemental fury, causing the spirits to disappear and a mist wall to trap the forest. The royal family escapes, but the truth about the past remains buried in memory.

Three years after Elsa's coronation, a mysterious voice calls to her, drawing the sisters toward the unknown. The awakening of the elemental spirits forces an evacuation of Arendelle and prompts a quest for answers. Grand Pabbie and the Trolls urge Elsa and Anna to seek the past to fix the present.

The mist parts when Elsa touches it, revealing the air spirit as a swirling tornado. She stops the storm by transforming it into ice sculptures that show memories from their father's history. This encounter marks the first direct contact with the forest's magic.

Elsa forms a bond with the fire spirit, a volatile magical salamander, as the expedition meets Northuldra and Arendellan soldiers. Despite lingering distrust, a fragile truce begins to take shape as they learn more about the forest's past. The fire spirit's temper mirrors the tensions between the peoples.

The Northuldra recount the legend of a fifth spirit who would bridge humans and nature. They suggest this magic could restore balance if understood. Elsa and Anna sense a purpose beyond their family's feud guiding their path.

Kristoff and Sven stay with the Northuldra while Elsa, Anna, and Olaf press onward. They discover their parents' wrecked ship and a map to Ahtohallan, the mythical river that is said to reveal the past. The discovery pushes the sisters toward a deeper truth.

Elsa ventures into the dangerous reaches of Ahtohallan and confronts the Nøkk, the water spirit guarding the path. She discovers the voice guiding her is the memory of young Iduna, and learns her powers are a gift tied to Iduna's selfless act of saving Agnarr. The revelation reshapes her understanding of magic and lineage.

Elsa uncovers that Runeard built the dam to suppress Northuldra and murdered their leader to spark the conflict. She conveys this truth to Anna, who is shaken by its implications. Olaf fades away as Elsa freezes, marking a personal cost to the revelation.

Understanding that true peace requires ending the deceit, Anna resolves to destroy the dam. She awakens the earth spirit Jötunn and lures it toward the structure, triggering a cataclysm of rock giants and a flood toward Arendelle. The dam's destruction sets the stage for the forest's release.

Elsa thaws and returns to Arendelle riding the Nøkk to confront the flood. She freezes the floodwaters, saving the kingdom, and Olaf is revived. Kristoff's proposal to Anna signals a new beginning as peace returns to the realm.

With the danger past, Elsa reveals her role as the bridge between people and magic—the fifth spirit. She abdicates the throne to Anna and becomes the protector of the Enchanted Forest, continuing to visit Arendelle in a peaceful balance. The sisters pledge to maintain harmony between the realms.

In a light post-credits moment, Olaf visits Elsa's ice palace and narrates the events to Marshmallow and the Snowgies. His cheerful recounting keeps the story alive in the palace and among Elsa's creations. The scene hints at a bright future for winter magic and friendship.