Tonight they will rise from the darkness beneath the city... to feed!

Corn grain contaminated with steroids produces large rats the size of small dogs who begin feeding on the residents of Toronto. Paul, a college basketball coach, teams up with Kelly, a local health inspector, to uncover the source of the mysterious rat attacks and they eventually try to prevent the opening of a new subway line as well as find the mutant rats nest quickly, or there will be a huge massacre of the entire city!