The night has wings, and fear has taken flight. In the dark there is nothing more frightening than being attacked by flying killers, especially genetically mutated and omnivorous swarms of bats! Dr. Sheila Casper (Dina Meyer), a zoologist specializing in the study of bats, is summoned by the terrorized town-folk of Gallup, Texas, where unexplained bat attacks have caused several grisly deaths. Sheila and her assistant, Jimmy (Leon), team up with the local sheriff Emmett Kimsey (Lou Diamond Phillips) to try to find a way to stop the bats. They discover that a scientist (Bob Gunton) commissioned by the military has tampered with nature and infected the bats with a genetic virus, causing the usually harmless mammals to become vicious killers. Can Sheila and Jimmy save the town before the military makes things worse?