You start off as someone with a normal life, until you get into a fight with a senator. After you kill him, his friends hit you unconscious. After that you wake up in a plane, which is crashing, and you go unconscious again. You wake up in the crashed plane, somewhere in the far future, where civilization has changed into tribes attacking survivor cities and villages.
Your job is to escape your current area, which is filled with spawners, ghosts, and mad kings that try to kill you. You can do quests to earn gold, so you can buy food and weapons at the local market. You can even build your own houses. There are lots of places to explore, such as undead prisons, or even a library maze.