Park ranger Angelica enlists the help of her dog handler ex-boyfriend, Viktor, to search for a missing woman in a dangerous Swedish nature reserve. The mission is complicated by a myth about the Cave Banshee, a vengeful spirit from Nordic folklore that once lured miners to their deaths in the reserve’s treacherous caves. As they venture deeper into the forest, Viktor begins to question his sanity and whether the Banshee is more than just a legend.