At “the Valley of Death” in Siberia, a giant Confederation robot piloted by “Alexander” vanquishes a Market robot and stomps on the cockpit containing its “robot jock,” killing him. At Market training headquarters, former champion jock Commander “Tex” Conway, robot designer-engineer Dr. Matsumoto, current champion “Achilles,” and Commissioner Jameson confer over why their robot’s new weaponry did not work against Alexander. Dr. Matsumoto believes a spy leaked information. Tex is angry because Alexander has killed nine Market jocks in a row, while the commissioner held Achilles in reserve. Jameson replies that he saved Achilles to fight for Alaska and its vast natural resources. Later, as Achilles trains new recruits, he is intrigued by an attractive woman named “Athena.” Jameson introduces Achilles and Tex to Professor Laplace, the female geneticist who developed the current crop of test-tube trainees, and asks for their cooperation because the Confederation is developing its own “gen jocks” for future battles. Laplace also wants Tex and Achilles to provide genetic material, in order to pass along their superior fighting abilities. Instructing the “tubies,” Tex explains that during a robot battle, he provides real-time tactics, Dr. Matsumoto runs technical machinery and video monitors, and the jocks follow orders as they control the robots’ actions. Athena asks Tex about one of his famous fights, in which he was overmatched, but was able to fire a laser into the Confederate robot’s most vulnerable spot. How did he discover the enemy’s vulnerability? Tex tells her it was “a lucky shot.” They all watch Achilles on a monitor as he prepares for combat. On international television, Alexander issues a taunt to Achilles, and the announcer asks disabled former jock “Ajax” if Achilles has a chance. Ajax reveals that the Market has a new secret weapon for this battle. As Achilles rides an elevator to the cockpit of the Market robot, the announcer claims that if he wins, he will be the first since Tex Conway to achieve ten victories. Achilles is wired in the cockpit so that every move he makes is transferred to the robot. When he raises a right foot, the robot instantly raises its right foot. The 120-foot-tall “Matsumoto 14” robot rises out of a large elevator shaft at the end of a field flanked by grandstands. The Confederation's robot, with Alexander in the cockpit, rises at the opposite end. The crowd roars. Dr. Matsumoto informs Achilles about the secret weapons, including a white-hot torch and a green laser. During opening salvos, however, Alexander deflects Achilles’ laser, prompting Sargon, one of the trainees in the control room, to wonder how the Confederation knew about it. As the two robots draw close, Alexander knocks Achilles down, but from his prone position, Achilles cuts into the opposing robot’s leg with his torch and topples it. As Achilles stands up, Alexander fires a steel rocket fist that flies off course toward the bleachers. Achilles steps in its path, but the huge fist knocks him backward into the stands, killing over 300 spectators. The announcer calls it the greatest disaster in the history of the games. Both the Market and Confederation are called to a tribunal, where Commissioner Jameson complains that the Confederation's flying weapon was in violation of rules concerning the hand-to-hand portion of the battle. He insists that the Confederation forfeit the match and abandon its claim on Alaska. However, the tribunal declares the match “inconclusive” and schedules a rematch. Achilles announces his retirement because he has already honored his ten-fight contract. The commissioner offers more money, but Achilles declines. At a party, Achilles gets drunk until the bartender refuses to serve him. Athena and Sargon tell Achilles he should not have risked defeat by saving the spectators, who knew the danger. Sargon would have let Alexander’s missile kill them, and Athena agrees. When Alexander enters, he congratulates Achilles on the 300 casualties. Sargon challenges Alexander to a fight, but the Confederation jock refuses to fight tubies. Sargon assures him they will fight next week, and Alexander promises to make his death “interesting.” Later, Achilles dreams about the grandstand disaster and awakens to find Athena sitting next to him. She brought him home from the party and undressed him, but when she studied his body, she found nothing visually special that made him a champion. Achilles claims what made him different was confidence mixed with fear. Athena answers that she was bred to have no fear. The next day, as Achilles gathers his belongings and leaves the compound, he gives Athena the “lucky” white scarf he wore during every victory. In town, he sees that a large poster of him has been defaced and the word “Coward” written on it. Achilles visits his brother Phillip’s family for a few days, and his nephews and nieces are happy to see their “Uncle Jim.” During rigorous training, Athena defeats her fellow trainees and is chosen to fight Alexander. Seeing the news on television. Achilles goes to Commissioner Jameson and asks to be reinstated to fight. His only request is that the bleachers be empty. Jameson accepts his return. As he prepares for the match, Achilles asks Dr. Matsumoto why he has not been briefed about new weaponry, and the scientist replies that the information will be available only when he gets into the cockpit for the fight. Achilles and Tex will have to trust him, but this way there will be no leaks. Later, when Achilles goes to the bar for a beer, Athena accuses him of quitting just to negotiate for more money. As Dr. Matsumoto prepares the video to play for Achilles, Tex arrives to complain about being left out of the weapons briefing. As an answer, Matsumoto reruns Tex’s famous fight and demonstrates why he should have lost. There was no way he should have known exactly where to fire, unless the Confederation warned him in advance. When Matsumoto pulls a gun, Tex admits, “You got me," but wrestles the weapon away and shoots the scientist, not realizing that Matsumoto turned on his camera. Tex makes Matsumoto’s death look like a suicide, and telephones Commissioner Jameson to announce he uncovered the spy, who then shot himself to avoid punishment. Athena goes to Achilles’ room to apologize and wish him luck, but injects him with a sedative. She puts on his combat gear and goes to the robot. When the Commissioner and Tex realize the jock is not Achilles, they call “condition red.” Achilles awakens and tries to telephone, but the line has been cut. Using a radio, he contacts his car and brings it crashing through a wall. In the robot cockpit, Athena overrides outside efforts to stop her, and Professor Laplace implores her to stop. When the commissioner gives an order to cripple the elevator, Athena uses the robot to climb out the elevator shaft. Jameson telephones the head of the tribunal, but is told the match automatically began the moment the Market robot took the field, regardless of who is running it. Hearing that Dr. Matsumoto killed himself, Achilles contacts Athena in the cockpit and tells her to activate instructions for the new weapons. An image of Matsumoto tells her the robot is equipped with magnesium flares that will blind the opponent for ninety seconds. Suddenly, the instruction tape cuts to Tex Conway holding a gun to Matsumoto’s head, and everyone in the control room sees it. They arrest Tex Conway, but he breaks free and leaps from a window to his death. On the field, Alexander’s robot goes airborne and lands in front of her. Achilles tells Athena to turn on the flares because Tex did not have time to tell the Confederation about them. She temporarily blinds Alexander, but he recovers quickly enough to knock her down and begin pounding her robot with his steel fist. The referee orders the robot jock to stop because his opponent is unconscious and he has won. When Alexander raises his foot to deliver a coup de grace, Achilles distracts him by landing his car next to the Market’s fallen robot. A tribunal vehicle hovers between the two robots, preventing Alexander from stomping the cockpit, and the referee orders him to leave or the Confederation will lose by default. Achilles climbs into the cockpit, removes the equipment from Athena, and kisses her. The Confederation master orders Alexander to leave, but he blocks the monitor transmission and stomps on the tribunal vehicle. As soldiers pull Athena to safety, Commissioner Jameson orders Achilles to stop the fight because the Market has won. Instead, Achilles kicks Alexander’s robot back and blasts into space. Alexander follows him into earth’s orbit. With the cockpit temperature rising, Achilles returns to earth and reconfigures the robot into a vehicle, but Alexander tips it over. Achilles slips out of the cockpit and runs to one of Alexander’s robot’s arms, which has been torn off. He crawls into the arm, rewires it, and fires its steel fist. The missile destroys the Confederation robot, but Alexander escapes. He and Achilles fight with metal pieces from their robots until they are too exhausted to continue. Achilles tells him they do not have to die. Alexander drops his weapon, and they bump knuckles as a gesture of peace.