Unturned

The game's story is can be found in written notes and environmental storytelling spread out across all of its official 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. In the basement of the lab, there are canisters containing zombies in stasis, and one of the canisters is broken. Also in the building there is an apology note, and the implication is that the writer was attacked before the note was completed. The Scorpion-7 lab is assumed to be ground zero for the start of the zombie outbreak, and while the exact origin and the cause of the outbreak remain vague, it is heavily implied that the virus was inadvertently created through the company's bioweapons research when a test subject escaped from their containment.
The player is introduced as one of the few survivors of the outbreak, alluding to the idea that the player has not "turned" into a zombie. The player has the option of helping the Coalition, an organization fighting the outbreak and locating survivors.
Sexton has built more lore for the world over the years. Some plot points revolve around real-world historical elements such as prehistoric Russia and the Roswell incident.