In the near future, as part of a new military recruitment and training program ("Project Adam"), a group of infants are selected at birth to be raised as soldiers. Undergoing extreme mental and physical training, they become virtual sociopaths, with no understanding of anything except military routine and war. A priority of the conditioning is that these soldiers are forbidden to speak unless spoken to, completely ignore physical pain, and to address whomever they are speaking to, women included, as "sir". At age 38, Todd (Kurt Russell) is a hardened veteran of many battles, but he and his unit are about to be replaced. Colonel Mekum (Jason Isaacs) introduces a new group of genetically-engineered soldiers, designed with superior physical attributes and a complete lack of emotions except aggression. Todd's unit's commander, Captain Church (Gary Busey) insists on testing the "new" soldiers' abilities against his own. But Todd, the unit's best soldier, is no match for Caine 607 (Jason Scott Lee). In the final trial, a fight between Caine and three "old" soldiers, two of Todd's comrades are killed, though Todd manages to gouge out one of Caine's eyes before he is defeated. Todd seemingly dies when he falls from a great height; but the body of a dead soldier cushions his fall, and he is simply knocked unconscious. Mekum orders their bodies dumped like garbage, and the remaining "old" soldiers are demoted to menial support roles. Todd and his dead comrades are dumped on the surface of Arcadia 234, a waste disposal planet with dangerously high wind velocities. Though badly injured, Todd limps his way toward a colony of humans who crash-landed there twelve years earlier, and have managed to survive and build a society from the planet's ubiquitous mountains of trash. Though they try to make him welcome, Todd has great difficulty adapting to the community due to his extreme conditioning. Todd's prior training of not speaking unless spoken to (and deliberately stunted social skills in general) make it difficult for him to answer questions in anything more than curt replies, and actually initiating a conversation is impossible for him. Many of the settlers are afraid of him, but he is sheltered by a settler named Mace (Sean Pertwee) and his wife Sandra (Connie Nielsen). Todd develops a silent rapport with the couple's mute son, Nathan, who had been traumatized mentally and physically by a snakebite. In a subsequent conflict with a curled snake, Todd teaches Nathan how to face it down and strike back to protect himself. However, his parents misinterpret the lesson, unsure of how to deal with Todd's apparent instability. Todd soon begins to experience flashbacks from his time as a soldier and mistakes one of the colonists (Michael Chiklis) for an enemy, nearly killing him. The settlers decide that Todd is too dangerous to live among them, so they give him supplies and order him to leave. Outside the colony, he sheds tears. He is confused, not understanding what they are, implying that this is the first time that he has cried. Shortly thereafter, Mace and Sandra are almost bitten by another snake while sleeping, and are saved at the last second by Nathan, using Todd's technique. Mace then realizes that Todd taught their son how to protect himself from the snakes and that he has an important role to play in their community, and decides to leave on his own to find and bring him back. The new genetically engineered soldiers arrive on a training exercise. Since the planet is listed as uninhabited, Colonel Mekum decides that the colonists' presence is unlawful and, as practice, orders his troops to slaughter them. Spotted by the arriving troops, Mace is killed just after he finds Todd. Though outmanned and outgunned, Todd's years of battle experience and superior knowledge of the planet allow him to return to the colony and kill the advance squad attacking the settlers. Nervous that a much larger enemy force may be confronting them, Colonel Mekum, grudgingly accepting Captain Church's advice, orders the soldiers to withdraw and return with heavy artillery. Using guerilla tactics, Todd outmanoeuvers and defeats all of the remaining soldiers, including Caine 607, who is finished off in hand-to-hand combat. Panicking, Mekum orders his ship's crew, composed of Todd's old squad, to activate a portable nuclear device powerful enough to destroy the entire planet, then orders the ship to lift off before they are back on board. When Captain Church objects, Mekum shoots him in cold blood. Before they can take off as planned, Todd appears, and his old comrades, now recognizing him as the ranking officer as a side effect of their conditioning due to their dismissal by Mekum, silently side with him over the army that has discarded them. Todd and his comrades take over the ship, tossing Mekum and his aides out onto the planet, and evacuating the remaining colonists just as the bomb detonates. Todd orders the ship to set course for the Trinity Moons, the colonists' original destination, then picks up Nathan and points to their new destination, while looking out upon the galaxy.
