In the near future, a super fungus code-named Ember Plague breaks out across the world. The fungal spores eat away at the host, transforming it into creatures called ember spirits. Ember spirits are not walking zombies, but retain some of their instincts, and their bodies produce deadly fluorescent spores, forming a dangerous "miasma zone." Civilization collapses, and survivors struggle to survive in ruined cities, quarantine zones, or wilderness.