Madison Lake (Annabelle Wallis) returns home to her husband, Derek Mitchell (Jack Abel), after her pregnancy causes her to be ill at work. During an argument, Derek hits Madison's head against a wall. Madison locks herself in the bedroom to avoid him and falls asleep. She later wakes up to find Derek dead, after having a dream of someone entering their house and violently killing him. The killer, who is still in the house, attacks Madison. The next morning, Madison wakes up in a hospital and is greeted by her sister, Sydney (Maddie Hasson). She is told that her baby didn't survive the attack. After being interviewed by police detective Kekoa Shaw (George Young) and his partner Regina Moss (Michole Briana White), regarding Derek’s death, Madison returns home. As there was no sign of forced entry into the house and Derek was known to be an abusive spouse, the police suspect that Madison is the murderer. Madison continues to experience vivid waking dreams in which a mysterious figure commits murder.