Anna consoles Elsa, who's crying tears of sadness, and hugs her. Then they part.
Anna is sent against her will into a body of water, a river, where she's met by one of the elemental spirits (the earth giants), but she avoids confrontation, leading her into a cavern, where she starts from the bottom and has to climb her way back out out.
Elsa purposefully makes her way into a body of water, an ocean, where she's met by one of the elemental spirits (the water nokk), and she directly confronts it, riding it to Ahtohallan, and enters into a cavern where she starts at the top and gradually makes her way further and further down.
Elsa sings a song of pure joy in a scene that's filled with magic and spectacle, and undergoes a critical transformation.
Elsa hops down to the deepest depths of Ahtohallan and finds the answer she's looking for, sacrificing her life in the process, giving up everything to deliver the message to Anna.
Anna receives the message, and in turn loses everything with the death of her sister, and Olaf dying in her arms.
Anna sings a song of pure grief in a scene that's grim and grounded, and undergoes a critical transformation, as she climbs out of the cavern into the sunlight, standing tall enough to see the entire enchanted forest beneath her.
Anna engages with the spirits she encountered earlier, using them to destroy the dam and break the curse. This causes a tidal wave barreling straight for Arendelle.
Newly revived, Elsa is aided by the spirit she encountered earlier, who helps her back to Arendelle, where she creates a dam of ice to stop the tidal wave from destroying Arendelle.
Elsa and Anna reunite, and Elsa consoles Anna, who's crying tears of happiness, as they embrace once more in a hug.