When 'Combat 3000', the new laser-tag centre, arrives near Sarah Jane, a young teenager called Lance Metcalf visits it, where he mysteriously disappears. When Sarah Jane starts investigating, she discovers twenty-four children have previously gone missing. Meanwhile Luke tries to master being funny but can't quite do it. He also doesn't understand games. Therefore Clyde takes Luke to 'Combat 3000'. Sarah soon discovers that there have been mysterious storms at the time of the disappearances and that Mr Grantham and Kudlak are working for the Mistress, leader of 'Combat 3000'. Luke and Clyde manage to survive Round One and are challenged to make it to the door to the championships, facing other expert 'Combat 3000' players. When Luke and Clyde are very close to the door, they are attacked. Soon, Clyde and Luke manage to escape and are locked in a room where they mysteriously disappear. Meanwhile, Mr Grantham points a gun at Sarah and Maria but Sarah uses her Sonic Lipstick to help her escape. Maria and Sarah arrive in a different room where they are then confronted by Kudlak.
They successfully escape Kudlak after creating a diversion, and return to Mr Smith, who informs them of who Kudlak is and the background to his race. He is a member of the Uvodni race, and they were part of a planetary alliance fighting against the Malakh. The Malakh won the ensuing battle, but the Uvodni would not quit, and continued fighting. Eventually, Kudlak was injured on the front line and forced to leave fighting to others. He was thus sent out as part of an Imperial Fleet to recruit "warriors" from other worlds. His ship [and, likely, all the others] were led by a Mistress, who kept the War-adrenaline in Kudlak alive. After decades of recruiting (mostly Terran) children via war-games - called 'Combat 3000' - Kudlak - or rather Mr Grantham - abducted Clyde and Luke. Meanwhile, Luke and Clyde rescue other children from their crates, including Lance and a girl called Jen.
Mr Grantham breaks into Sarah Jane's home, but is overpowered by electrocution. Back on the Uvodni ship, the children make their way to a shuttlecraft, but are again captured. Sarah Jane and Maria blackmail Grantham into transmatting them to the Uvodni ship, where they find and talk to The Mistress. When Kudlak brings the children to The Mistress, everyone is reunited. Preparing to kill them, Kudlak is stopped by Luke, who has discovered a message made by the Uvodni Emperor ten years ago, revealing an Armistice has been made with the Malakh. Not programmed to recognise "peace" as a concept, the computer Mistress had buried the message and kept leading Kudlak in recruitments. With the truth revealed, Kudlak destroys The Mistress, releases the children and swears to do what he can to reunite all the surviving past-recruits with their families.