A city lost in the mist, fragments of Mercy Springs, California, have appeared throughout different timelines and worlds, leaving behind one frightening question: what happened to its residents? On a cold Friday night in 1983, scientist Tinson Miller forces the appearance of a Black Door—a terrible anomaly rumored to lead to other worlds. With the door trapped in stasis in his basement, Tinson attempts to force it open, crossing thresholds that should not be crossed. But in his search for scientific discovery, Tinson unleashes a terrifying entity that threatens to consume Mercy Springs and possibly all of reality.