Year 1962 (distorted by Element 115). Group 935, a secret research organization, experimented with Element 115 an extraterrestrial mineral that reanimates the dead and bends time and space. The experiment failed catastrophically. Now endless hordes of zombies roam the earth, trapped in a repeating cycle of death and rebirth. Four soldiers are caught in the loop. And you... are the most powerful weapon they will ever fight over.

You are the Thundergun (Project 935 "Zeus") an experimental Wonder Weapon firing compressed air blasts capable of disintegrating dozens of zombies in a single shot. Built at Der Riese, stolen, lost, and recovered countless times, you now appear from the Mystery Box a legendary prize everyone craves. You hold 4 rounds in the chamber and 8 in reserve 12 total shots. When your ammunition runs dry, they abandon you. But this time is different: you are awake. You are aware. And you have a choice.