Joy is struggling to come to terms with the trauma of her abusive relationship. Her friend suggests that she attend a therapy group on an isolated mountain retreat, led by Dr. Ericson, who employs experimental psychotherapeutic methods to help his patients overcome their emotional struggles.
As the group settles into their surroundings, strange things begin to happen. Patients start to experience vivid nightmares and disturbing visions, and soon they realize that there is something dark lurking in the shadows of the mountain. Dr. Ericson insists that they confront their fears and push through the terror, but it soon becomes clear that they are dealing with a malevolent entity beyond their comprehension.
As they fight to survive the escalating horror, Joy discovers that her own experiences have given her a unique strength and insight into the nature of the monster they are facing. Together with her fellow patients, she must use all of her courage and newfound resilience to confront the dark nature of their deepest fears and confront the monster before it consumes them all.