The game begins with the player, the Doom Slayer, wakes up chained to a coffin after hundreds of years being trapped in Hell. A zombie comes to kill the Doom Slayer, but he breaks free from his chains, kills the approaching zombie, and kills the rest of them with the Pistol. In the next room, the Doom Slayer finds his suit of armor, the Praetor Suit, and puts it on. Right after that, the Doomslayer learns that the UAC lab on Mars has been overrun with demons, and that almost everyone on the base is either dead or they turned into zombies or demons. This is the result of leading scientist Olivia Pierce and her followers performing rituals to literally unleash Hell on Mars.