A team of US soldiers, led by Major John Cafferty (Tahmoh Penikett), embark on a mysterious mission in Afghanistan, only to awaken from an amnesiac haze in a military hospital with no memory of their past or the events that transpired during their deployment. As they try to piece together what happened to them, they begin to experience strange visions and encounters with an otherworldly power source. With their memories slowly returning, they must confront the betrayals that led to their amnesia and the true purpose of their mission.