Anna, Elsa, Kristoff, Olaf and Sven leave Arendelle to travel to an ancient and enchanted autumn-bound forest to find the origin of Elsa's powers in order to save their kingdom.

Tells a twisted tale of two estranged sisters whose reunion is cut short by the rise of flesh-possessing demons, thrusting them into a primal battle for survival as they face the most nightmarish version of family imaginable.