After the tragic accident that claims the life of his wife, Lisa, psychologist Cal Jamison relocates, seeking a fresh start for himself and his young son, Chris. They move from the familiar streets of Minneapolis to the bustling metropolis of New York City, where Cal embarks on a new role as a police psychologist for the NYPD. However, as fate would have it, he steps into a whirlwind of horror as the city grapples with a spree of horrific and ritualistic child murders. The first victim, a young boy, is discovered lifeless in an abandoned movie theater, sending shockwaves through the community. A frantic policeman, Tom Lopez, calls in the grisly find, suggesting that these heinous acts are the work of a sinister Hispanic cult engaging in a twisted form of brujería.
In an effort to understand the depth of this darkness, Cal takes on the daunting task of assessing Tom, who is now spiraling into paranoia and recounts tales of the cult's chilling leader. The tension escalates with the horrifying discovery of a second victim, found brutally eviscerated upon a makeshift altar beneath a Staten Island dock. Seeking answers, Cal turns to his housekeeper and nanny, Carmen, who practices a benign version of brujería, providing protection charms for both him and Chris. Yet the situation spirals further out of control when Tom, consumed by fear and paranoia as he senses unseen watchers, tragically takes his own life in a diner.
Cal's personal life also takes a turn as he starts to develop a bond with his girlfriend, Jessica. Their relationship adds a thread of hope amidst the chaos, but soon, they are entangled in something far more sinister when a mysterious Caribbean figure named Palo attempts to make off with a necklace from Jessica at a party. Unbeknownst to her, this encounter sets a dangerous chain of events into motion. Upon returning home, Cal discovers Carmen performing a ritual on Chris, leading him to angrily confront her, despite Carmen's fervent assurances that she is there to protect his son.
As the summer solstice approaches, Chris embarks on a trip with his wealthy Aunt Kate and Uncle Dennis to their country home, blissfully unaware of the mounting dangers. In the urban chaos, Cal and Jessica meet with Oscar Sezine, a friend of Tom's, who reveals a chilling forecast—the cult is planning a sacrificial rite in just four days. In an attempt to shield Chris from being a sacrificial target, Oscar performs a purification ritual. However, calamity strikes when Jessica is stricken with illness, marked by a grotesque boil that births baby spiders, a horrific manifestation of the cult's malevolence.
Receiving a distressing call from police lieutenant Sean McTaggert, Cal rushes to his home, only to find it in chaos, with McTaggert on the brink of a breakdown and clutching a damning document that details a powerful businessman, Robert Calder, and the ritual murder of his own son. However, tragedy befalls Cal again as McTaggert succumbs to despair and takes his own life shortly after. With the threats mounting and tension thickening, events spiral into a nightmarish climax as Cal arrives at Kate and Dennis's home, only to find Kate has mysteriously disappeared to run some errands. Perhaps more horrifying is Dennis's tale of a past trip to Sudan, recounting a human sacrifice that ended a drought, planting seeds of dread in Cal's mind.
The sickening realization dawns upon Cal when Palo and Calder confront him, revealing their dark intentions for Chris, claiming he is destined to be a sacrificial lamb. In a desperate fight for survival, Cal makes a heart-stopping escape through the window, only to discover his worst nightmare in the boathouse—Kate's lifeless body. Soon, he is captured and taken to an abandoned factory where the cult plans to execute Chris's sacrificial rite. In a harrowing struggle against overwhelming odds, Cal manages to save his son by stabbing Dennis, and with the help of his friend Marty, who arrives in the nick of time, they battle the cultists in a chaotic showdown.
As the grand finale unfolds amid the backdrop of the warehouse, Cal tracks down Calder and confronts him in a nail-biting fight, culminating in the death of black-hearted antagonists to rescue Chris. As relief washes over him, they narrowly escape, yet not without scars from their harrowing ordeal. The couple seeks refuge, allowing them to build a life at last. Some time later, Cal, Jessica, and Chris find contentment on a serene farm. Their peace, however, is abruptly shattered when Cal stumbles upon an altar in their barn, laden with religious icons, offerings, and remnants of ritual sacrifice, revealing that Jessica has delved back into darkness, confessing her actions were meant to keep them safe. As she chillingly declares, “I did it for us. We'll be safe now,” the screen fades to black, leaving viewers shaken and entranced by the unsettling conclusion.
