It happens in a split-second. One moment, customers are happily shopping in the Save-A-Lot grocery store. The next instant, they are transformed into bloodthirsty psychotics, interested only in slaughtering one another and committing unimaginably atrocious and frenzied acts of violent depravity. Only Jack, Sammi, Angie and Marcel seem immune to the insanity that has infected the rest of the tow...