Two forensic clean-up men discover a deadly mythological siren hidden in the basement of a remote cabin in the Norwegian woods. She never utters a word, unable to tell her story, but the pieces of the puzzle soon come together: she's been held captive for decades for reasons soon to surface.

["Thale" is a mythical character in Nordic folklore called the "huldra". According to the myth a huldra is a beautiful creature with female attributes living deep in the woods. It is said that it seduces men that works in the woods by humming a beautiful song, and they never return to their village. You can recognize a huldra by its cow tail.]