The disease that the cockroaches are carrying is a type of deadly virus that is spreading rapidly through the population of children in Manhattan. Susan Tyler, the entomologist working to contain this epidemic, becomes increasingly desperate as her efforts fail to produce results.
In a last-ditch effort, Susan creates a new species of insect that is genetically engineered to kill the cockroaches carrying the virus. This new insect, the Judas Breed, is designed to have a short lifespan and to die out after one generation in order to prevent any unintended consequences.
For a time, the Judas Breed appears to be successful in controlling the cockroach population and halting the spread of the deadly virus. But three years later, Susan discovers that the Judas Breed has not died out as intended. In fact, the species has evolved into a new form of monster that is capable of mimicking human form.
These new creatures, which are large and gruesome in appearance, begin to prey on humans in the city. Susan realizes that her creation has run amok and that the only way to stop the monsters is to destroy them all.
As the creatures continue to spread and multiply throughout the city, Susan and a team of scientists and police officers must work together to find a way to eradicate them before they wipe out the entire population of Manhattan.