In the aftermath of Theresa's mastectomy, Nicolas Cage takes his family—comprising children Madeleine Arthur, Brendan Meyer, and young Julian Hilliard—to his late father’s secluded farm. One fateful night, a vibrant meteorite crashes onto their property near the well, sparking a series of bizarre occurrences. The following morning, Ward Phillips, a hydrologist surveying the area for a dam project, arrives with the local mayor and sheriff to witness the strange celestial event. However, things take a darker turn as Nathan and Lavinia start witnessing uncanny developments surrounding the meteor, which mysteriously vanishes.
Ward soon discovers an oily sheen in the groundwater. His tests, yielding startling results that mimic the meteor's colors, lead him to caution the Gardners against consuming the water. As the family quickly falls under the meteor's sinister influence, Jack becomes obsessed with the well, claiming to communicate with a 'friend' beneath its surface, while eerie plant life and insect behavior manifest around him. In a chilling turn of events, Theresa, distracted while preparing dinner, injures herself by cutting off two fingers. Nathan rushes her to the hospital, leaving Benny outside, who reappears late at night, bewildered and claiming that time passed differently for him. Meanwhile, Lavinia tries fruitlessly to reach Nathan, but they remain disconnected. Upon their return home, Nathan lashes out in an unexpected fit of rage towards both Benny and Lavinia, their family dynamics fraying as crops wither and tension escalates.
Desperate to save her family, Lavinia performs a ritual with a copy of the Necronomicon, offering her blood in a grim act of devotion, even as she injures herself. Sudden shrieks from Jack and Benny echo from the alpaca stables, prompting Theresa to rush to their aid as the ominous "Color" starts to wreak havoc outside. In a horrific twist, a bolt of energy fuses Theresa and Jack into a grotesque entity. With their electronic devices failing and the family trapped, Nathan and the children are forced to confine Jack and Theresa in the attic, away from the harmful light. As the situation worsens and the alpacas exhibit grotesque mutations caused by the Color, Nathan confronts the necessity of mercy, ending their lives with a shotgun. Yet, his diminishing sanity prevents him from doing the same to his loved ones.
In a panic, Lavinia and Benny attempt to flee on horseback, but their horse bolts in fear. Benny believes he hears their dog’s cries echoing from the well. However, when he investigates, the Color consumes him. Nathan, now fully unraveled, locks Lavinia away with Theresa and Jack, both of whom have transformed into monstrous forms. As Ward and the sheriff return to the farm, alerted by a local resident who stumbled upon mutated livestock, they break into the attic to rescue Lavinia just in time. Nathan, overwhelmed by despair, believes he has lost his family entirely and ultimately takes drastic measures against the grotesque beings before him.
In the ensuing chaos, Ward helps Lavinia escape as the Color surges ominously from the well, while Nathan, misinterpreted as a threat, is shot by the sheriff. Lavinia chooses to stay with her ailing father, prompting Ward and the sheriff to seek out their neighbor, Ezra, played by Tommy Chong, who has also been impacted by the Color. Upon their arrival at Ezra's cabin, they discover his lifeless body, along with a haunting audio recording suggesting that the Color desires to reshape its surroundings into something familiar. The duo barely escapes another surge of the Color, but the sheriff meets his fate at the hands of a transformed tree.
Ward rushes back to rescue Lavinia, only to find her fully overtaken by the Color. A surreal funnel of the Color erupts from the well, drawing them into a vision of its alien origin, where tentacled entities loom. As the reality around them begins to shatter, Ward narrowly escapes an assassin-like apparition of Nathan. He barricades himself in the wine cellar, yet the relentless distortions of reality continue to ravage their home, leaving Ward solitary as the sole survivor amidst the ashen remains of the once-vibrant farm.
In a haunting epilogue, an older Ward stands upon the newly constructed dam, now saturating the land where the Gardner family once lived. He shares that few recall the tragic events, but he vows never to drink the water, stating that what he witnessed—the Color—was a herald from realms beyond human comprehension. As he departs, an insect twisted by the Color flits by, serving as a chilling reminder of the unnatural horrors that transpired.
