Viral experimentation is the key to ingenuity at the Midlands Biological Research Centre, located in the English countryside of Cannock Chase. This is where Professor Brian Newman is at the cutting edge of bacteriology. Though even he has reservations when it comes to tampering with Mother Nature.

When he discovers a potentially lethal virus in living bat specimens, he decides to withhold the results from administration and destroy those that somehow evaded death. But before he’s able to carry out his plan, he inadvertently releases them from their cages and into the laboratory where they manage to escape through a window and out into the world. The not-so proverbial bat is now out of the lab.

Reported attacks begin to surface, causing panic and consternation among the mostly rural population. That is, until the bats spread beyond the town’s borders and into the big city of Birmingham where they create mass carnage and chaos.

Newman and his colleagues desperately seek a solution, testing out theories without producing any viable results. But with the wave of bats growing by the hundreds and a mob of locals ready to impale him with their pitchforks, time is a luxury he can’t afford to waste.