Swarmed

Kent Horvath tests a new pesticide on eight wasps. Six die, but two survivors carry extremely high pheromone levels that trigger aggressive swarming. This discovery seeds the escalating threat.

A janitor accidentally frees the surviving wasps, unleashing a deadly attack. The janitor is killed as the insects go on the spree in the building. This marks the start of the crisis.

In the morgue, buzzing signals release the second wasp from the janitor's mouth, sealing the mortician's fate with a fatal sting. The body is found with the wasp nearby, confirming the threat.

Cristina Brown leads a bees class when she is called to investigate the mortuary death. The interruption pulls her into a potential link between insects and a citywide danger. The investigation expands beyond insects.

Agent Doug Heydon informs Cristina about Kent's research and the janitor's death, prompting a deeper look for a possible link. The team starts to see a broader pattern behind the outbreaks.

Q is summoned to a home plagued by yellow jackets and is urged to restock supplies. He warns Kent not to use the experimental formula, foreshadowing trouble.

Q sprays the nest with the blended formula, and venom tests reveal a mutation that makes the wasps’ venom far more lethal and their aggression far more intense. The threat expands beyond the sprayed nest.

The Chief of Police uses blackmail to pressure Mayor Gibson over secret meetings with Washburn, signaling a political dimension to the crisis. The mayor contemplates a payoff to keep quiet.

The treated nest is stored in a trash compactor, but about a quarter survives, including the queen. They chase the queen to the truck, where Q administers antivenom before collapsing. The remaining wasps disperse, ready to cause more trouble.

Venom tests in the lab confirm the lethality matches the janitor’s death. Cristina and Kent realize the annual burger cook-off will act as a magnet, drawing the swarm into the city.

The first wasp reaches Mayor Gibson’s office and kills him by stinging his eye. Ellie Martin discovers the body and kills the intruder with a shotgun, signaling the crisis's reach into politics.

Heydon warns the Chief to halt the cook-off, but the threat is dismissed. The swarm attacks the crowd, killing a reporter and other attendees as two wasps crawl along a hose to sting Washburn in the mouth.

Kent, Cristina, and Rafe lure the swarm toward a garage and use a flamethrower to destroy the bulk of the insects. A fire wipes out the main swarm, but the queen survives and begins laying eggs, hinting at a recurrence.

Kent and Cristina start dating and share a quiet dinner, but the film closes on an uneasy note as the queen’s eggs suggest the threat may not be over.