The Doom features a space marine, known as the Doom Slayer, battling demonic forces that invade various locations, primarily Mars and Earth, after the Union Aerospace Corporation (UAC) opens portals to hell. The Doom Slayer, often a figure of immense power and rage, is driven by vengeance against the demons for past transgressions. The overarching plot involves humanity's struggle for survival against these infernal invaders, with the Doom Slayer acting as the ultimate protector.