Thale is a Huldra (a mythical woodland creature). She goes back to nature after defeating the organization that was looking for her. The men who found her and helped her (Leo and Elvis) return to their lives, which are better due to the good fortune helping a Huldra brings.
Leo and Elvis are a cleaning crew that go to clean the house of a deceased old man who lives in the woods. While they talk Leo eventually reveals he has aggressive cancer and Elvis reveals he has a child. While cleaning they find a mute naked woman who was submerged in a bathtub. Elvis is sympathetic towards her and starts playing diary recordings of the old man’s to figure out who and what the woman is. They find out her name is Thale and that she is “Huldra” (a creature from Norwegian folklore that is essentially a wood nymph or spirit of the forest). The old man had worked for an organization that captured her and studied her, but he was so drawn to her he smuggled her out and raised her. To keep her in hiding from both the organization and her own kind he removed her tail and practiced some kind of method that involved submerging her in a milky liquid in the bathtub.
Eventually, Leo, Elvis, and Thale are attacked by the organization that, now that the old man is dead, has found her. Leo and Elvis are tied up, blindfolded, and interrogated by a leader named Hvittkledd, who asks them what they know about Thale but they give him nothing. While this takes place Thale, who had been effectively hiding in the bathtub once again, emerges and takes out all the soldiers who attacked them, and Leo and Elvis are saved by the wild Huldra in the woods. Leo and Elvis return home Elvis shows Leo his family and Leo reveals that his cancer has mysteriously gone away completely (it is implied that this is due to them helping Thale because in some legends of the Huldra it is said that if you help one or make one happy they will do you a favor or give you good luck/health). The film ends with Thale returning to nature.