A disease carried by common cockroaches is killing Manhattan children. In an effort to stop the epidemic an entomologist, Susan Tyler, creates a mutant breed of insect that secretes a fluid to kill the roaches. This mutant breed was engineered to die after one generation, but three years later Susan finds out that the species has survived and evolved into a large, gruesome monster that can mimic human form.

Sully is a rascally ne’er-do-well approaching retirement age. While he is pressing a worker’s compensation suit for a bad knee, he secretly works for his nemesis, Carl, and flirts with Carl’s young wife Toby. Sully’s long- forgotten son and family have moved back to town, so Sully faces unfamiliar family responsibilities. Meanwhile, Sully’s landlady’s banker son plots to push through a new development and evict Sully from his mother’s life.