It happens in a split-second. One moment, customers are happily shopping in the Save-A-Lot supermarket. The next instant, they are transformed into bloodthirsty psychotics, interested only in slaughtering one another and gleefully committing unimaginable atrocities and frenzied acts of violent depravity. Only Jack, Sammi, Angie, and Marcel seem immune to the madness that has infected the rest of the town. But can they stay alive long enough...