In the heart of a dense forest, mercenaries Reeves and Karlsson regroup with their comrades - Gantz, Capper, Evans, and their commanding officer Smith - alongside two hooded, bound captives. As they reconvene, Reeves recounts their hurried escape from hostile forces, while Karlsson quickly sedates the seriously injured Capper. Meanwhile, Evans becomes increasingly agitated upon discovering the jeep's engine has been cruelly sabotaged, twisted to resemble a living serpent, compounding the sense of dread in the air.
As Reeves and Gantz proceed to a nearby farm, they come across an unsettling orange powder scattered around, sending Reeves' stomach churning. The atmosphere thickens with tension as Evans’ nerves unravel further, his erratic actions mirroring the jeep's debilitating state. While Karlsson cares for Capper's injuries, he sedates Evans to regain some order, allowing Reeves and Gantz to inspect the surroundings.
Their search leads them to "group D," another cluster of mercenaries along with two captives who have met grisly ends in a barn. The silence is abruptly disrupted by music drifting from a storage container, where they find a woman playing tunes. She panics when the sound ceases, prompting Karlsson to sedate her while Smith decides she should accompany the group.
Just as they prepare to leave, an enemy flare illuminates the night sky, and Smith commands a quick retreat, abandoning Capper to the chaos. Gantz and Evans retaliate against a hooded figure, but Evan's indecision proves fatal as he hesitates, trying to help their fleeing comrades. The team rushes across a field and discovers an abandoned armored personnel carrier, seeking refuge from relentless pursuers.
As they discard the vehicle's cargo, Gantz fires at another hooded figure, but one prisoner strikes back, fatally wounding him. In a moment of swift action, Reeves takes down the attacker, and they seek shelter inside the vehicle, only to be met with a barrage of sounds from the outside as attackers attempt to breach their defenses.
Amidst the confusion, Karlsson distributes tranquilizers to calm the group's nerves, while Smith instructs Gantz to address the tank's engine. Gantz's effort is stymied when he finds a decaying corpse in the front seat, only adding to their mounting unease. As they rummage for tools, they uncover bottles of orange powder branded "Kratos," with Annabella, one of the surviving captives, explaining it signifies "strength and power" in ancient Greek.
Seizing an opportunity, she secretly pockets a flare gun from a toolbox, her motives masked in mystery as the group remains unaware of her intentions. As the fog of slumber dissipates, Reeves is haunted by vivid nightmares, including a monstrous Gantz and heated arguments surrounding Smith’s ever-present notebook. Confused upon awakening, Reeves seeks answers from Annabella, who claims she can't recall how she ended up in this dire situation.
The next morning presents no relief as the argument from Reeves' dreams recurs, with Smith obstinately refusing to reveal the contents of his notebook. Gantz struggles to repair the engine but is halted by a distance too great to traverse, only to discover orange powder residue on the machinery in a growing atmosphere of tension.
Gantz’s gaze is abruptly drawn to a nightmarish figure in a gas mask lurking outside, sending him cliff-diving back into the comforting embrace of Karlsson’s sedatives. Smith then assigns Reeves the daunting task of fixing the engine, while Karlsson reviews the files in the vehicle, finding unsettling dossiers detailing the mercenaries and their fates—grim reports that even include Smith himself. In disbelief, Smith asserts he knows nothing of such a fate, yet Reeves’ examination of the corpse reveals a dog tag with Evans' name.
As Reeves works on the engine, Capper reappears to mock their hopes, taunting Karlsson about her injections and implying Smith holds secrets he isn’t disclosing—an idea igniting an argument between the two. Amidst this upheaval, Annabella makes a desperate move, using the flare gun to fatally wound the unsuspecting Smith. In a swift turn, Karlsson retaliates against Annabella, only to discover too late that she herself has been accidentally shot by Smith during his attack.
In the aftermath, as Reeves finally breathes life back into the engine, Capper's lingering threat continues to cast a shadow over the group. Fueled by the strength from the Kratos powder, Reeves takes it upon himself to end Capper's threat for good, a goal he achieves as Capper meets a grisly end. However, the eerie silence that follows leads Reeves to uncover one last survivor—a woman who had been lying unmoving amongst the wreckage.
As she comes to her senses, the stillness of the surroundings quickly gives way to chaos. The hatch, once stuck tight, now clicks open easily to her touch. The tranquility of the forest is shattered by the sudden arrival of figures clad in hazmat suits and gas masks, accompanied by another suited individual wearing protective gear. Upon discovering the sole survivor inside the vehicle, he coldly remarks, "It worked, good," before ordering the execution of Reeves.
The scene shifts back to the serene forest, interrupted by a loudspeaker exclaiming ominously: > "An experiment is about to begin..." A soldier emerges from a sterile white box, heralding an era fraught with terror and uncertainty ahead.
