Paul is seen desperately searching for supplies in a storehouse, trying to elude the chaos of a catastrophic event. Sirens wail, distant explosions rumble, and cries of panic fill the air as he clutches his two infant sons close, offering them words of comfort amid the overwhelming fear, reassuring them that all will be well.
Fast forward fifteen years—much of humanity has been decimated by a relentless pandemic, leading to the collapse of society. Paul, alongside his twin boys, Joseph and Thomas, find themselves navigating life in a dilapidated farmhouse. During the daylight, they scavenge whatever they can, only to retreat at nightfall to defend themselves against horrific creatures that thrive in the dark.
One evening, as Thomas returns from the neighboring Rose family farm, it becomes clear that he is the more daring of the brothers, while Joseph embodies a pragmatic approach, always looking for strategies to improve their dire circumstances. After dinner, an unsettling noise echoes from the cellar. After three attempts by the creatures to breach their home, the banging comes to an eerie halt.
The following morning, Paul discovers alarming scratches on the cellar door, leading him to reinforce it. Meanwhile, Joseph reveals his secret project: he has been restoring a rugged utility buggy stored in their barn. Under Paul's guidance, he learns to start the engine. With their father's instruction, Joseph sets off with Thomas to gather materials for the cellar door's fortification. However, Thomas, harboring feelings for Charlotte Rose, expresses his desire to visit her family's farm and parts ways, telling Joseph to fetch him before night falls.
While journeying back from the Rose farm, a misstep leads Thomas into a cave, leaving him concussed and vulnerable. As darkness descends and Joseph returns home without his brother, Paul sets out on a search. Upon finding Thomas in the cave, they decide it’s safest to remain there until the morning. Yet, as creatures begin to close in on them, Paul ignites a flare for protection, but tragically gets his hand trapped, leading to a violent explosion that eliminates the threats at the cost of the cave collapsing around them.
Back at home, Joseph cleverly uses himself as bait to trap one of the creatures, planning to investigate it further. The following morning, he manages to rescue Paul and Thomas from the cave, but finds his father badly injured. Thomas insists they must take Paul to the Rose farm where he can receive proper medical care, fearing his father won't survive without it. Upon their desperate arrival, Mr. Rose and Mrs. Rose reluctantly inform them that they cannot spare any medicine but offer to let Thomas stay for their safety. Tensions rise when Joseph and Thomas argue, leading Joseph to make the tough decision to take their father back home, leaving Thomas behind.
Later on, Thomas is caught by Charlotte while searching for medicine to help Paul. She guides him to where it's hidden, and he vows to return, but a farmhand catches him attempting to sneak back past the gate, mistaking him for a looter. The young boy is restrained, facing potential punishment from the armed farmhands.
Back at home, Joseph soon discovers a horrifying truth: the creatures are burrowing beneath their farmhouse and intend to break through. Meanwhile, at the Rose farm, chaos ensues as the monsters arrive, slaughtering everyone except Thomas and Charlotte, who manage to escape back to Paul’s farm. Awakening, Paul devises a courageous plan to confront the creatures. Joseph prepares a devastating trap, orchestrating several gallons of fuel to create an improvised incendiary device. To buy time for Charlotte and the brothers to escape, Paul locks the door behind them and valiantly holds off the creatures until the bomb detonates, sacrificing his own life in the process.
The following day, Charlotte is left to bury her parents. Together with Joseph and Thomas, the trio embarks on an uncertain journey to scour the neighboring farms, hoping to discover any remaining survivors in their perilous world.
