As S.U.M.1 embarks on his duties at Outpost Cerberus, the burden of a 100-day deployment looms overhead, much like the dusty landscape surrounding him. His journey to this remote outpost—an emblem of human endurance—serves as a striking reminder of life's fragility, particularly as refugees flee toward Exilium, escaping the unseen terrors that lie outside. Once S.U.M.1's tank comes to a halt, he steps into the cramped quarters of the outpost for the first time.
Upon entering the living quarters, he faces immediate challenges when the door jams, compelling him to ascend the sentry tower for communication with command. It is here that he receives news of V.A.X.7's unscheduled retreat for medical reasons, along with some assurance that all remains stable within the outpost. Equipped with the daily access code, S.U.M.1 navigates the confusing corridors and eventually reaches his modest accommodations—a basic space with six bunks and a communal table. Though untidy, he begins to arrange his scant supplies and meticulously cleans a glass cup until it sparkles.
As the monotony of duty sets in, the days blur together. S.U.M.1's mind occasionally drifts to visions of carefree children against a tranquil blue sky, only to be jolted back to reality by the daily alarm signaling the dwindling time left in his service. Physical exercises, showers, and quick check-ins establish a rhythm, interspersed with the rare pleasure of a rationed cigarette.
Outside, an ongoing wave of audio messages encourages survivors to seek shelter in Exilium, promising safety from the Nonsuch threat. S.U.M.1 remains disconnected from this reality, engrossed in maintenance and surveillance routines, fueled by curiosity about the seemingly absent Nonsuch. The ever-watchful security cameras hover over the outpost, observing its activities without blinking.
As time progresses, S.U.M.1 senses a foreboding atmosphere enveloping Outpost Cerberus. A general broadcast reports a sudden attack on Outpost Lalops, and S.U.M.1's apprehension escalates as he gazes from his tower balcony, witnessing distant explosions and the terror of the Nonsuch's victims, each echoing a darker chapter of the world outside. What hidden secrets lurk beyond the shadows?
The isolation weighs heavily upon S.U.M.1 as he begins to succumb to the crushing loneliness. The abrupt and dismissive nature of his communications with his superiors amplifies his feelings of disconnect. In this desolate space, he unexpectedly forms a bond with a resident rat he names Doc, sharing his sparse rations and occasionally even giving a little of himself. However, this companionship morphs into a battle against hallucinations, issuing a growing unease regarding his mission's true intent. Despite relaying his findings—like the dog tag found hanging from a tree, accompanied by a lifeless bird—to his commander, he only encounters dismissive replies, further undermining his belief in the mission’s purpose.
As he descends deeper into the bunker, S.U.M.1 spots a bloodstain on the wall, leading him to suspect that V.A.X.7 may have taken his own life. This unsettling thought drives him to pry open V.A.X.7's locked locker, where he finds a sketchbook and a radio. The drawings depict not just the Cerberus outpost but also the defense circle Gram, igniting his interest and determination to unveil the truth.
S.U.M.1 attempts to reach out to Gram, but the surrounding perimeter triggers a painful implant, halting his progress. Undeterred, he resolves to communicate via visuals, waving and shouting from a nearby tree, yet his voice finds no reply. Frustration mounts when he accidentally shatters a glass while cleaning it, inflicting a deep cut on himself.
While tending to his injury next to Doc, the melodic strains of music suddenly resonate from V.A.X.7's radio, mixing with the voice of neighboring soldier K.E.R.4 calling out for V.A.X.7. When S.U.M.1 tries to pose as V.A.X.7, he is promptly recognized and rebuffed. The communication ends with a warning that future attempts will be futile.
As his time at the outpost continues, S.U.M.1’s mental condition worsens dramatically. The investigation into peculiar coincidences only intensifies his paranoia. A power outage during his review of outpost video history causes the files to vanish upon restoration, and the lack of clarity regarding the expected arrival of a MAC team compounds his fears, further unraveling his grip on reality.
Amid a raging storm, the sudden appearance of MAC generates both dread and desperation in S.U.M.1. Initially feeling relief at the newcomer’s arrival, his perception shifts toward hostility after a physical altercation occurs, resulting in Doc being carelessly knocked against the wall. This tension escalates when MAC tries to access the internal camera system and historical archives, pushing S.U.M.1 to brandish a weapon in a futile attempt to regain authority over the situation. Their second confrontation results in defeat for S.U.M.1, who is compelled to listen as MAC recounts tales from past military encounters with the Nonsuch.
As revelations gradually unfold, S.U.M.1 is increasingly convinced that MAC’s narratives are fabrications intended to deceive him. His growing mistrust fuels a fervent pursuit of the truth, culminating in the unlocking of the bunker’s archives, where he discovers unmistakable proof that V.A.X.7 succumbed to madness. Motivated by newfound resolve, S.U.M.1 shares his theories with K.E.R.4 over the radio, suggesting that their mission to evacuate humans to Exilium is merely a ploy to control dwindling resources, while the elite continue thriving.
As S.U.M.1's fixation intensifies, he spirals into madness, leading him to a tragic act when he kills Doc, his once-trusty companion. Swallowed by rage and despair, S.U.M.1 emerges from the bunker naked, confronting a monstrous figure that incites his deepest fears. Armed with antlers scavenged from a tree, he launches a brutal attack, only to discover with horror that the creature was V.A.X.7, forever solidifying his conspiratorial beliefs.
In a tumultuous emotional storm, S.U.M.1 returns to the bunker to face MAC with his shocking discoveries, issuing dire threats against the newcomer. The MAC’s sabotage of S.U.M.1's 4x4 computer serves as a painful reminder that even the most desperate attempts at searching for truths can ultimately be futile.
As S.U.M.1 limps toward the DC perimeter, experiencing a mix of physical agony and momentary clarity, he confronts a new challenge: the high-voltage cable. With arduous effort, he uncovers the buried wire and severs it, unleashing a cacophony of alarms that pierce the twilight air. His task complete, S.U.M.1 propels himself toward Gram, urged by rising urgency. Upon reaching the tower, he is met with sheer devastation: debris covers the floor, and K.E.R.4 is mysteriously absent. The metallic aroma of blood fills the atmosphere, a grim reminder that the menace of the Nonsuch remains alarmingly tangible.
As S.U.M.1 surveys the havoc around him, his attention is drawn to the shattered windows, from which chaos unfolds—vehicles driven by unseen forces converge in a whirlwind of destruction. The downfall of the DC and Gram's eerie silence grant the Nonsuch unchecked momentum. Just when hope seems to vanish, MAC reappears to help S.U.M.1, only to fall prey to a cunning Nonsuch operative.
In a moment of horror, S.U.M.1 witnesses his once-reliable vehicle being commandeered, its fate sealed alongside that of its last passenger. The calculated coldness of the approaching Nonsuch sends him dashing for the bunker, but the usual access codes falter—his wrist computer lies in ruins. After three painstaking attempts, he finally breaks into the bunker, greeted by an automated reassurance of evacuation.
Yet, this fleeting sense of comfort evaporates swiftly as the Nonsuch onslaught proves insurmountable. As the bunker’s structural integrity collapses around him, S.U.M.1 realizes his supposed sanctuary has transformed into a death trap. The film concludes with a lone Nonsuch breaching the bunker’s perimeter, its chilling gaze set on S.U.M.1, who fires ineffectually at the alien menace, his bullets falling dismally short against the impenetrable steel...
