In the dead of night, a terrifying mystery unfolds in Anya Taylor-Joy's gripping psychological thriller. She plays Sarah, a woman whose life is shattered when her husband begins exhibiting violent and complex behaviors in his sleep—actions he could never consciously perform. Desperate for answers and fearing for her safety, Sarah delves into the shadowy world of sleep science, encountering a reclusive specialist played by Ethan Hawke who suggests her husband's condition may not be a disorder, but a doorway. As the nocturnal episodes grow more dangerous and targeted, Sarah is forced to question everything she knows about reality, memory, and the man she loves, racing against time to uncover a truth buried deeper than the subconscious. This chilling film masterfully blends the tension of a domestic thriller with the unsettling dread of a supernatural horror, creating a suffocating atmosphere where the line between dream and waking life terrifyingly dissolves.