Behind a high-security military facility, Mr. Whicks oversees a test of Serum XT1258 on a soldier, who instantly mutates into a zombie and attacks the surgeons. The remaining serum is moved away for disposal, but chaos ensues as the soldiers, fighting over a map, misstep and knock down a follower. In the confusion, one serum barrel falls out and rolls behind a bowling arcade, leaking and contaminating the ice cream.
Tim, an arcade employee, shares the tainted treat with his friends: Mike, his crush Cindy, and Vanessa, Mike’s ex-girlfriend. All four lose consciousness and wake up transformed into zombies, yet they still perceive themselves as human. Cindy begins to suffer a stomachache, and Vanessa and Tim are unable to summon an ambulance because the phone operators speak and hang up too quickly—everything in the normal world seems sped up to the level of a zombie’s perception, but they brush it off as faulty connections.
Seeking help outside, they encounter Nick, a military private who joins them in the search for a working phone. They stumble into a bar where the patrons turn hostile, and the group showcases unusual strength and endurance. Nick reveals he was also exposed to the serum and suspects it has infected a large portion of the population; the five of them appear immune because their infection came through dairy, which may have neutralized the serum’s toxins. Convinced the military will try to cover up the incident, Nick urges them to stay together for safety.
Nick attempts to spy on Colonel South and Dr. Richter to learn more, but his efforts are thwarted and he later goes to steal information about the serum. Meanwhile, Cindy and Tim check on Cindy’s family, while Vanessa and Mike hurry to a job interview. Tim’s actions spiral, and he ends up killing Cindy’s parents when they throw dynamite at him as he asks for permission to see her; he catches it and throws it back just before it explodes. Vanessa’s attempt to confront her would-be employer results in the man fleeing into his bedroom. The situation grows bleaker as Colonel South’s forces tighten their grip and Nick is captured, his brain waves sped up to supposedly “understand humans again.” South unveils the plan to eradicate the infected, and Nick’s zombie form pushes him to resist and escape.
The four survivors—Tim, Cindy, Mike, and Vanessa—reunite at the bowling arcade, where Tim’s rival Danny and his drunken team challenge them. Drunk opponents mistake zombies for humans, so the plan hinges on keeping them in that misperception long enough for a breakout. Mike and Tim face Danny’s crew while Cindy and Vanessa keep the opposing team distracted and disoriented. The moment reveals itself when Mike is decapitated in the scuffle, though his head remains alive, and the group clutches victory by eliminating Danny and his friends with Nick’s help.
With a bold new plan, Mike proposes infecting the soldiers at the headquarters to turn the tide. They recruit the dead bowling teammates by resurrecting them with the tainted ice cream, disguising them as corpses inside a disposal truck heading to the base. They nearly get captured by Colonel South’s containment unit, but Mike sacrifices himself by activating a grenade with his mouth, delivering a crucial distraction and allowing the others to advance.
The zombies reach the headquarters and Nick steps forward as a diversion for Colonel South while the others work to spread the infection among the soldiers present. Enraged, South orders Nick to be taken alive, but the attack continues, and a new zombie town begins to form.
Tim, Cindy, Vanessa, and the remaining zombies build a new settlement—“Zombie Town”—in memory of Mike and Nick. Colonel South and Dr. Richter plan to torture Nick for treason, but Nick replies with a defiant, chilling line: > I'm not a soldier. I'm a zombie.
In the aftermath, Zombie Town stands as a stark testament to the chaos unleashed by the XT1258 experiment and to the uneasy, enduring bond between the living and the undead.
