Plot
Ruben Castle, a brutish and alcoholic New York City police officer, quits his job and becomes sober, allowing him to reunite with his estranged teenage daughter, Mackenzie. Ruben decides to bring Mackenzie with him to Colorado, where he plans to start a new life. En route, the pair become stranded near the rural small town of Buffalo after their trailer suffers a tire blowout. Mackenzie rushes in her father's car to find a tow truck, and crashes into the vehicle of the newly-appointed town sheriff, Harriet Perdue. Ruben and Mackenzie park their trailer in a campground, and become acquainted with the townspeople. Ruben encounters Harriet several times, and learns she is investigating a series of mysterious cattle mutilations, which have spurred conspiracy theories among locals ranging from UFOs to a Satanic cult in the area.
Ruben and Harriet strike a friendship over their shared careers as police officers. One night, Harriet gives Ruben a ride, and is called to the scene of a burning barn, where Harriet unsuccessfully attempts to save a bull. Meanwhile, Mackenzie, who is on a date with Wayne, a local deputy, witnesses a car speeding from the barn and decides to follow it into a wrecking yard. A crash ensues between the two vehicles, and two men are apprehended for the arson, which they staged to inspire fear in the townspeople.
Local newspaper publisher Joe Hiatt provides Ruben background on the cattle mutilations, which have been plaguing Colorado and Wyoming, and recounts sightings of strange black helicopters flying over the region. Meanwhile, Joe publishes editorials about the events, alienating him from the town mayor, as well as local cattle baron Ben Morgan. Ruben reluctantly grows fascinated with the events. After relapsing and getting drunk one night, Ruben visits Harriet and makes sexual advances toward her, but she rebuffs him. Ruben leaves and encounters a large grain mill truck driving erratically, leading him to follow the vehicle to a rural fenced industrial compound.
The next morning, ranchers bring a mutilated cow found on their property to the doorstep of the police station, creating a cause célèbre. Ruben inquires to Joe about the grain truck he saw the night before, and Joe informs him the fenced complex is an abandoned military outpost. Ruben begins drinking heavily again. Shortly after, Joe is found dead in his office, attributed to a heart attack.
Harriet sends samples of the cattle organs to a pathologist in New York, who informs her that the tissue is riddled with the bacteria clostridium botulinum , which appears to have been modified via gene splicing. The pathologist indicates that his knowledge of the only surfacing of such bacteria was in government experiments conducted in 1969 researching germ warfare. Meanwhile, Ruben covertly visits Ben's ranch. He witnesses a black helicopter land, and a mercenary named Steele confront Ben, who has been coerced by his nephew, a Washington, D.C. politician, to allow them to use his cattle for medical experiments. Steele threatens Ben and reprimands him for not silencing Joe. Later that night, Ruben departs to Ben's ranch, where he begins shooting down equipment used to procure the cattle. He is chased by a black helicopter, but hides in a cattle corral.
The following morning, Ruben leaves Mackenzie at the airport to take a flight back to New York, but she is abducted by mercenaries before boarding the plane. Meanwhile, Ruben confronts Ben at his office, finding him mysteriously ill and vomiting blood. Ruben forces Ben to drive him to the ranch at gunpoint, but Ben crashes the car and stumbles onto the road before his abdomen inexplicably bursts, eviscerating him. Harriet is forced to arrest Ruben for kidnapping, though she insists to her superiors that both Joe and Ben were murdered due to their knowledge of the cattle experimentation. Ruben is visited in his jail cell by an operative who threatens him, insisting that if he remain quiet for 24 hours, Mackenzie will be spared.
Ruben and Harriet flee to the military outpost and manage to sneak inside. Shortly after, a fleet of police officers and vigilantes descend on the complex. Ruben holds Steele at gunpoint, while Harriet locates Mackenzie. In the rafters of the warehouse, Steele stabs Ruben, who responds by shooting him, causing Steele to fall to his death. Peck and several other operatives open fire, before the three flee on foot as the trucks depart. Outside, police and vigilantes open fire on one of the helicopters, shooting down a dead cow it is lifting. The large group of townspeople, along with Ruben, Harriet, and Mackenzie, watch as the helicopters flee into the distance.
