A masked maniac with a penchant for a monster-themed board game is playing his own twisted game with the women of a small American town. Each time the dice are rolled, another victim meets a grisly end. Returning home to mourn the death of her murdered sister, Keegan befriends local cop Roger and reclusive cinema projectionist Billy — but soon finds herself in the killer's sights.

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!