The game's story is spread out across all of its maps. On the Washington map, there is a lab belonging to a company known as Scorpion-7. Outside the lab, there is an overrun military unit and within the building, in the basement, there are canisters containing zombies in stasis, one of which is broken. An apology note can also be found in which it appears the writer was attacked before the note was completed. It is assumed that this lab was ground zero for the start of the outbreak. The exact origin and the cause of the outbreak remain vague, but it is heavily implied that the virus was inadvertently created through bioweapons research the company was conducting, and the outbreak was caused by the escape of a test subject from their containment. The player is introduced as one of the few survivors, alluding to the idea that the player has not "turned" into a zombie. The player can help the Coalition, the organization fighting the outbreak and locating survivors.
