Joy, a survivor of domestic violence, joins her friend Carmen and her therapy group on an isolated weekend retreat in the Canadian Rockies. Led by the enigmatic Dr. Dunnley - whose methods are experimental and, at times, dubious from Joy’s outside perspective - the experience eventually shatters the border between reality and delusion. Joy begins to suspect that they are being stalked by her abuser, when in truth, the entire group will be forced to confront a threat even more terrifying than the monsters of their past.