Plot
Amidst the desolate desert scape of Sirius 6-B, a trio of humans approach a defunct communication bunker to transmit its distress beacon toward Earth. As they attempt to close the distance, Screamers kill two of them, while one manages to make it inside to safety and triggers the beacon.
Two months later, the interstellar spacecraft Medusa sent by Alliance Command approaches Sirius 6B. The ship carries a volunteer rescue team dispatched in response to the beacon. After the crew emerges from hypersleep, medical officer Schwartz checks each member's vital signs, while pilot Olof Soderquist comments about his adventurous Viking ancestry.
Before planetfall, the ship's AI briefs the crew about the discovery of Berynium on Sirius 6B, the ensuing civil war that followed the discovery of lethal radiation from mining, the creation of the Screamers to end the stalemate, and the application of TAB devices which prevent detection from a Screamer. It is presumed that all Screamers have become inert since eradicating all life on the planet. The last known remaining survivor, Alliance Colonel Joseph Hendrickson, committed suicide by destroying his ship on re-entry to Earth 13 years ago. There has been no communication from Sirius 6B in the ensuing years until the emergency SOS was received.
Specialist Rafe Danielli says that in 6 days Sirius 6B will encounter a planet-wide solar meteor strike, categorized as a class-10 Magellanic storm. This constrains their mission time to just under a week. Commander Andy Sexton questions Lt. Victoria Bronte about her true reason for volunteering on the mission. She insists there's no hidden motive and regards this as "just another mission."
Upon landing, Sgt. Romulo issues TABs to the team and explains their operation since it is uncertain if the screamers have become inactive. Each team member synchronizes their timers to a six-day return window and Soderquist remains behind to monitor the ship's status.
DAY 1
The team deploys and tracks the location of the distress signal, while they are under surveillance by an unseen observer. They spot a hillside bunker and investigate. Upon entering its cave entrance, Commander Sexton is injured by radioactive acid leaking from the ceiling- a by-product of Berynium mining. Further inside they discover a darkened Screamer factory. The assembly line and manufactured Screamers are dormant. Lt. Bronte recounts that screamer production was completely automated since their inception. The presence of human bones confirms that screamers were scavengers who used parts of victims to substitute for a lack of raw materials. One of the team acknowledges that Screamer technology would be worth a fortune on Earth, but Commander Sexton reminds them that Alliance Central has classified this information as top secret.
The team spends the night in the bunker. While everyone is asleep, Commander Sexton sneaks into the factory to download the screamer design specs by charging one of them. Unbeknownst to him this procedure reactivates the factory.
DAY 2
Meanwhile, on Medusa, Soderquist performs maintenance on the ship's systems. A screamer has sneaked onboard and kills him. The following morning the team crosses the hillside and detects a life-form reading within an old Berynium mine. En route, they are fired upon by unseen assailants and take a defensive position. Romulo is gravely injured by deflecting a screamer attack on Lt. Bronte. He insists the team leave him behind while more screamers approach. As they leave he triggers a grenade destroying them and himself. Commander Sexton orders an immediate return to Medusa, citing the screamers are too dangerous to continue the mission, despite protests from Lt. Bronte.
DAY 3
Upon their return to Medusa, Schwartz stumbles across Soderquist's mutilated corpse. Lt. Bronte notices the fuel cells have been drained to the point of preventing their return journey. The security log reveals that a screamer got onboard and tapped the fuel. Commander Sexton orders a search mission in the area to locate more cells. Lt. Bronte suggests they seek out the people from the mines who attacked them earlier. Despite protestations, Commander Sexton agrees. The team cremates Soderquist's remains outside the ship and set out at daybreak.
DAY 4
Lt. Bronte surprises a survivor named Hannah but manages to gain her confidence after saving her from a screamer. She leads the team into the mine to meet the rest of the occupants. Commander Sexton states their objective while Lt. Bronte adds that the planet will soon be hit with a devastating meteor storm. She offers a safe return to Earth if they help find fuel cells. The leader of the survivors, a man named Guy, warns the team that the latest variety of screamers can impersonate human beings, who are only distinguishable by bloodletting. He tests Lt. Bronte by slicing her hand and his own- proving themselves to be human. They are informed that there were once 400 survivors but the screamers killed off most of them, and are shown a series of tunnel explosives to be detonated if the screamers gain entry to the mine. The remaining survivors say they subsist by scavenging for "what the land gives us." Lt. Bronte strays from the group and discovers 3 human teenagers bound to metal racks who plead for release. She notices blood and viscera on a dissection table and promises to return for them.
Upon rejoining the team Lt. Bronte relates her discovery. They release the prisoners who are revealed to be screamer cyborgs. They destroy one but Rafe Danielli is killed by another. The two remaining screamers escape and kill a guard. Back at the collective, Hannah begins showing signs of acute stress by compulsively sharpening her bone knife and muttering to herself. The screamer cyborgs ambush the group and kill a few survivors before Commander Sexton and Lt. Bronte destroy them. They hear screamers entering the mine and start to evacuate, detonating the tunnel explosives in their wake.
DAY 5
Commander Sexton announces that he's found another abandoned mine where they can spend the night. Guy says he knows of a power relay station where they might be able to find some fuel cells. During the night Hannah warns Lt. Bronte about Guy's "inhuman-like" behavior, but he interrupts her and she walks off. Privately Lt. Bronte reveals to Guy that she's the daughter of the deceased Alliance Colonel Joseph Hendrickson who had presumably committed suicide upon re-entry to Earth. Guy remarks that he was a fearless commander who must've had a reason for self-destructing his spacecraft.
DAY 6
The group enters the power relay station. Hannah mentions to Lt. Bronte that she has "never seen Guy sleep" and suddenly puts her knife to Guy's throat proclaiming he's a machine, but she's overpowered and killed by Commander Sexton. The group proceeds down the corridor while Schwartz elects to remain momentarily to cover Hannah's corpse. A screamer descends behind Schwartz and kills her. The team returns to find blood on the wall and several screamers advancing. A masked stranger appears ahead of them and insists they follow him to safety. As they run past he fires an electromagnetic weapon at the pursuing screamers which deactivates them.
Safe inside his laboratory, the stranger introduces himself as Eugene Orsow. They warn him about the impending meteor storm and their need for fuel cells to return to Earth. Orsow says there aren't any fuel cells, and that screamers are following them from the mine settlement and will converge on their position in just a few hours. He says the perimeter defense might hold them off.
Lt. Bronte catches Commander Sexton reviewing the downloaded screamer algorithms. He offers to cut her in on the profits but she refuses. Bronte speaks with Orsow who says he was a close friend of her father's. Orsow refutes her statement that Colonel Henrickson committed suicide. He reveals that he and her father were close friends but had a falling out over the former's invention of the screamers. He adds that Henrickson would only have destroyed his ship if screamers had been aboard.
Commander Sexton discovers Orsow installing fuel cells to the power grid. Orsow admits he doesn't want the group to leave Sirius 6B to prevent screamer technology from reaching Earth. Sexton wounds him with his electromagnetic weapon, removes Orsow's TAB, and begins to pull out the fuel cells. As the perimeter defenses deactivate, Orsow attacks Sexton but is killed. Sexton leaves with the fuel cells to join the others.
The facility computer announces that the compound has been breached and an automated self-destruct sequence has begun a 3-minute countdown. Rafe Danielli suddenly appears before the group. Startled by his presence since he was seen killed by the screamers, Danielli appears as having been simply wounded, but suddenly kills Madden revealing to have been transformed into a screamer. The pair escapes. The Danielli screamer encounters and attacks Commander Sexton, but is destroyed by Lt. Bronte. A dying Sexton implores Bronte to take the information disc containing screamer technology back to Earth, but she refuses and crushes the disc. Bronte and Guy leave Sexton and escape the facility as it is self-destructing.
Outside the pair deduce that Danielli is a new type of screamer: a hybrid resulting from biochemical implants into a human host. The storm is about to arrive so they hastily return to Medusa. Once inside they discover Madden has already gained entry and become a hybrid screamer from Danielli's attack. Madden suggests Bronte become a screamer like himself, but Guy destroys him using the electromagnetic cannon.
Bronte installs the fuel cells enabling Medusa to take off just as the meteor storm descends. The pair enter cryogenic sleep for the two-month return journey to Earth. They awaken when the ship arrives in orbit and Bronte notices she is pregnant but farther along than she should be for the allotted time. Guy assures her everything will be ok. She turns to him in horror as his eyes have gone black indicating he is a screamer hybrid. She pounds his chest with her fists while a view of the ship enters Earth's orbit. Inside her womb, the fetus raises a hand and protrudes a claw.
The final frame bears the message "The Beginning..."
