Set along the North California coastline, Adelaide Wilson (Nyong'o) reluctantly returns to her beachside childhood home with her family and finds that she is haunted by unresolved trauma from her past along with a string of eerie coincidences. As darkness falls after a tense day at the beach, the Wilsons discover four figures standing in their driveway. They soon realize this is only the beginning of their troubles as they find that the four figures are terrifying and uncanny opponents: doppelgangers of themselves.