The world is in an epidemic, a virus transferred by animals infected causes any bitten subject to lose any and all mental restraint, and it will cause them to act wild and it forces the subject to be extremely wild and the subject's only goal will be to attack anyone them find.

Class 1-A is the only group of people left who haven't been bit. The class had taken refuge in their school. They had blocked off the doors. They had been using the supplies from the market and nearby gas stations.