A huge biochemical experiment was conducted, in which poisonous gas accidentally escaped into the atmosphere.
The climate of the world was greatly affected. Many people fell sick and then became zombies. Only a handful of people survived. It is currently impossible to develop an antidote. To help the few survivors, certain warriors aren’t able to fight zombies. They are referred to as apocalyptic heroes. Help the warriors acquire modern weapons and mounts, and then use their abilities to take on the enemy.