Summer break is almost over. Four youngsters are punished by having to clean the school and can only leave when everything is spick-and-span. At first sight, it looks like the school was left by a very enthused group of students, but soon they realize a horrible event has taken place. While trying to unravel the mysterious havoc, they are chased by four marauding, masked people. These four Gas Masks seem like the Four Horsemen of the Apocalypse, as they represent Famine, Pestilence, War, and finally Death. They set traps and hunt the young students down. While the youngsters are fighting to survive, they discover that they’re more involved with the ravaged school than they first thought.