In post-apocalyptic Sweden, a deadly virus has turned most of the population into mindless creatures. A group of mercenaries must brave the dangerous woods and fight their way through infected hordes to find an antidote. With time running out, they face various obstacles such as tunnels, fog, and a mysterious black-uniformed enemy. As they make their way towards the rumored source of the antidote, they must confront their fears and use their tactical skills and martial arts to survive.