As Paul, a dedicated projectionist navigating the urban sprawl of Detroit, becomes captivated by the haunting tale of the Roanoke Colony's mysterious disappearance, the lights in the theater abruptly flicker and die, plunging him into a foreboding darkness. In this eerie void, he quickly realizes that the staff and patrons have vanished, leaving only their discarded belongings as remnants of their presence. In this abandoned space, Paul encounters a security guard holding a flashlight, which becomes a beacon of survival against the lurking malevolence in the shadows. However, the guard's fate is sealed when his light goes out, plunging him into the abyss.
As the unsettling darkness envelops him, Paul hears a distant plea for help emanating from a nearby department store. Driven by urgency, he races to assist, only to find his own headlamp has extinguished. The narrative shifts to a hospital where Rosemary (played by Thandiwe Newton), clad in scrubs, frantically scours the sterile halls, desperately calling out for any signs of Manny as her voice echoes through the empty spaces.
The next day, Luke Ryder (portrayed by Hayden Christensen), a television reporter, awakens to a jarring new reality—one devoid of power, littered with abandoned cars and discarded clothing. His former vibrant apartment has turned morose, a silent grave. Upon arriving at his station, he discovers an unsettling recording that captures the moment his girlfriend disappeared as the lights flickered off.
From Chicago, a grim broadcast advises, > "Keep a light on yourself at all times." As Luke grapples with this alien world, he is drawn to the dim glow of a bar powered by a makeshift generator. Here, he meets a young boy named James Leary, who clings to hope that his mother will return from the nearby church by the street.
Days stretch into a harsh struggle for survival as Luke scavenges for batteries and checks abandoned vehicles. It is during this critical time that Rosemary finds him, her own quest for Manny providing a glimmer of hope amidst their despair.
On the third day of darkness, Paul reemerges, his face marred by a severe concussion, and shares the chilling tale of Roanoke's settlers, over a hundred of whom mysteriously vanished overnight. As he recounts this ancient enigma, they begin to ponder if their own lives are entwined with the fate of those lost in history.
When they discover the word "CROATOAN" carved into a fence post, it serves as a chilling reminder that perhaps the secrets of Roanoke hold the key to understanding their plight. Together, Luke, Rosemary, and Paul must face the unsettling reality that they may be next to disappear into the enveloping dark.
With the hospital's generator failing and Paul in dire need of medical help, Luke devises a bold escape plan to Chicago, navigating through the sepulchral streets with Rosemary in search of batteries for their flashlights. As ominous shadows close in, they feel an irresistible pull towards a solitary streetlight, which seems to beckon Rosemary with a supernatural charm. But as the luminescence flickers and goes out, she vanishes, leaving Luke in a state of disbelief.
Simultaneously, in the bar, the generator sputters ominously, as if to deliver a dire warning. In a desperate search for James, Paul descends into the murky tunnels beneath the bar, only to lose track of his young companion amid the swarming darkness. Remarkably, James remains safe, his glow-stick necklace providing a precious source of light as Paul's fate hangs by a thread.
Luke heroically manages to retrieve a truck from the bar and narrowly escapes with James, relying on the generator to breathe life into their vehicle. As they pass the church, James's yearning for his mother compels him to disembark. Luke, sensing something darker, returns and finds the eternal message "CROATOAN" etched into a sign. Just as he attempts to revive the truck's battery, darkness engulfs him, and he disappears as mysteriously as Rosemary did before him.
Now alone, James seeks refuge in the dimly lit sanctuary of the church, surrounded by flickering candles that threaten to burn out. Awakening the next morning, he discovers a lone candle still aglow, only to be taken aback by the sudden presence of Briana, a young girl who has survived thanks to her solar-powered flashlight. Though she offers companionship and comfort, James is acutely aware that their peace will soon be overshadowed by the inevitable return of darkness.
As they leave the church, James and Briana come across a police horse munching on fallen apples and decide to commandeer it for their treacherous journey towards Chicago. As the sun sets, shrouding the land in shadows, the camera pans back to the bar, where the silhouettes of Luke, Paul, and Rosemary linger, seemingly watching James and Briana venture into the growing dark. Briana's solar-powered flashlight flickers to life, providing a reassuring glow that promises to shield them from the advancing shadows as they embark on their uncertain journey ahead.
