The film begins in Iraq during 2010, where a small squad of soldiers navigates a war-torn desert and stumbles upon a manmade underground cave. Their leader, Lt. Griggs, instructs two soldiers, Jimmy Tratner and Mike Santino, to explore. As they delve deeper, Jimmy films the journey, but their light flickers and eventually fails. Their terrified screams echo and the night vision captures a horde of bats erupting from the darkness. Jimmy tries to persuade Santino to retreat as they tread over a horrifying river of human skulls. However, Santino is drawn to the back of the cave, revealing a Latin inscription that hints at a darker fate.
Fast forward to 2013, in New York City, we meet Detective Ralph Sarchie, who is found engaged in a desperate attempt to save a tiny bundle, which tragically turns out to be a deceased infant. The coroner urges him to let go, but he struggles with the overwhelming grief. Soon after, Sarchie and his partner, Butler, respond to a call about a domestic disturbance. The couple arrives at the home of Jimmy Tratner, who lets them in after Sarchie asks for his wife. On the couch, they discover her severely beaten. In a tense struggle, Jimmy attacks Sarchie, inflicting a cut on his arm, before he is apprehended—his fingernails disturbingly bloodied.
Later, Sarchie and Butler receive an alarming report from the local zoo — a woman has thrown her 2-year-old son into the lion's pit. Thankfully, the lions are away, but the boy suffers serious injuries. Amid the chaos, they lose track of the woman who immediately escapes. As they search for her, Sarchie experiences unnerving behavior in animals and encounters the woman frantically clawing at the ground while loudly reciting The Doors lyrics. Meanwhile, a man in a hood slips away deeper into the enclosure, just before Sarchie narrowly avoids two lions.
At the precinct, they meet Father Mendoza, who believes that the woman, Jane, is possessed. Despite Sarchie's skepticism, he solemnly takes Mendoza's contact information. As they complete paperwork, Sarchie watches a video message from his wife Jen and daughter Christina, bringing a moment of respite. Later, Sarchie learns of another case where a deceased father seems to be calling his daughter, stating, “shut the door, the damn door.” This gives Sarchie a chilling connection to Jane’s earlier incident at the zoo.
The detectives receive a new lead, suggesting that a family fears their house is haunted, given inexplicable disturbances. Sarchie and Butler investigate and, while exploring the basement, Sarchie finds a corpse wrapped in a tarp, later identified as Lt. Griggs. The family reveals that Griggs had a sordid past with Jimmy and Santino, both of whom were dishonorably discharged after a violent incident. Sarchie's investigation leads him back to the notorious painter, Mike Santino, who he realizes is connected to the strange events unraveling around him.
As Sarchie’s family situation deteriorates, he grapples with mounting evidence of supernatural phenomena invading their lives. Notably, Christina’s room becomes increasingly haunted, with encounters that terrify her, prompting conflict between Sarchie and Jen. Meanwhile, Jane escapes a mental facility, adding urgency to the investigation.
Delving deeper, Sarchie discovers a sinister inscription linked to Santino's paintings and realizes its horrific implications—it's a portal to Hell. A series of confrontations culminates when Sarchie, Butler, and Mendoza confront Santino at his residence. Tragedy strikes as they fight off a possessed Jimmy, leaving Butler fatally wounded.
In a frantic race against time, Sarchie is confronted by disturbing visions and haunted by Jane’s tragic fall onto his vehicle. When Santino kidnaps his family, Sarchie launches a desperate rescue operation. After a long and grueling exorcism, they manage to drive the malevolent force from Santino, ultimately ensuring the safety of Jen and Christina.
In the aftermath, with the threat vanquished, Sarchie embarks on a new chapter in life, stepping away from the police force and joining forces with Mendoza to combat the darkness that once shadowed them both.
