Whilst escaping from a cult in a frantic drive, Laura unexpectedly goes into labor and pulls over, giving birth to a son named David. Fast forward eight years, and Laura is striving to lead a normal life with her child. One fateful night, as she checks on David, she is horrified to witness a group of strangers surrounding his bed before the door slams shut, sealing her fear. In distress, she seeks help from her neighbor, Susan, who calls the police. However, upon returning to David's room, the mysterious figures have vanished, leaving David in a sickly state.
Two police officers, Paul and Steve, respond to her call. While Paul shows compassion towards Laura, Steve dismisses her concerns as mere delusions. After providing Laura with his card for any future needs, things take a dark turn when David vomits blood, prompting an urgent trip to the hospital. Despite doctors' best efforts, they can’t determine the cause of David’s ailment; they warn Laura that recovery seems bleak. Exhausted, she falls asleep at his bedside and dreams of her traumatic time in the cult, where she recalls a chilling banner that reads: > "He Is Coming." To her astonishment, she wakes up to find that David has seemingly recovered.
Back home, Laura informs Paul of her decision to sell the house and start anew, but he convinces her to reconsider. Their budding connection is interrupted when David screams, leading them to discover him convulsing in bed. After David is readmitted to the hospital, Laura overhears troubling discussions among the medical staff. Fearing for their safety, she takes David and seeks refuge at Susan's house. Unfortunately, upon returning from gathering supplies, she is met with a horrific sight—David has brutally murdered Susan and is consuming her flesh, all while appearing fully recovered. In a desperate move, Laura decides to cover up this atrocity, painting "He Is Coming" alongside the cult's symbol on the wall in a bid to shift blame.
As they attempt to escape once more, Steve uncovers details of Laura’s dark past through newspaper articles, revealing her real name, Anna, and her past abduction by a horrifying cult. He suggests to Paul that Laura may be experiencing a breakdown, but Paul remains sympathetic. Seeking answers, Laura visits Jimmy, another cult escapee, who unveils a shocking truth: she was impregnated by a demon during her captivity. The nightmare deepens when Steve and Paul discover Jimmy dead, with a grotesque display of crosses in his mouth and the warning, > "He Is Coming," painted in blood.
During their stay at another motel, David shares a chilling dream with Laura, leading her to feel utterly helpless. That night, a group of cultists invade their motel; in a desperate stand, Laura fires at them, but the horror turns as they reveal themselves to be Steve and two other officers. Realizing the full extent of her entrapment, Laura returns to the cult's house to perform a dark rite designed to summon the demon, hoping to save David by offering him to the entity. Just as she is about to sacrifice him, Paul and another officer burst in, causing the demon to vanish. In a frenzied moment, she attempts to stab David, but the officer intervenes, fatally shooting her first.
The chilling conclusion unfolds in a hospital room, where David lies in bed. In a twist of fate, Paul feeds him his own blood, revealing through haunting flashbacks that he has been the orchestrator behind Laura's torment, a member of the very cult she sought to escape. As the demon appears within the hospital, David embraces his dark lineage, hinting at an insidious future as the film draws to a close.
