This is a speculative summary of the story of Id Software’s unreleased DOOM 4. Because of the game’s tumultuous development and the limited information available, the opening story summary is split into two versions. These two stories might have been one early version and one later version of the same storoy, or possibly they were stories that ran alongside each other. Until more information about the game becomes known, we can't really say.
The year is 2038 and the world is facing a pandemic known as the Kafere Plague. The private healthcare provider AGIS has capitalized on the crisis while there’s growing civil unrest at the government’s handling of the situation. In New York, the military have been called in to deal with the civilians leading to further tension between the self-proclaimed resistance and the soldiers. Suddenly, in the middle of Manhattan, a giant otherworldly structure emerges and emits a wave of energy that begins to transform and tear apart the city. Demons invade the streets and people are possessed by hellish spirits causing an all-out war. A civilian, caught in the chaos, must take up arms alongside the resistance to fight back the hordes of hell and close the gates they came from.
The UAC space station Valhalla is orbiting Earth. After an incident, a marine ejects from the station in an escape pod and lands in New York, where a horde of demons have been unleashed. The marine must fight back the hordes of hell and close the gates they came from.
The civilian/marine fights the demons throughout New York. Locations include a large library ripped in two by the hellwave, the subway, an underground resistance base, a school turned into a shelter for the sick, a massive favela-esque stack of apartments and a selection of urban environments. As the invasion is linked to the UAC, the civilian/marine heads to one or several UAC facilities, including one that’s built underwater, to try and close the gate. As the invasion grows stronger, buildings, vehicles and other things in the city start turning into flesh and bone. How the story goes after this is unknown at this point. Either the player enters the hell dimension itself or the world becomes so twisted that even more “hellish things” happen to the world.
Most of the details of the “Hellwave” opening story come from assets from the vertical slice demo that was intended to be shown at E3 at one point. Mentions of the AGIS healthcare provider can be found both in concept art and on environmental assets, while mentions of the year 2038 and the Kafere Plague have only been spotted in said assets. That the player would be a civilian caught in the middle of a feud between a resistance group and the military was revealed by Id Software early in development during job listings and casting calls. The “Crash Site” opening story is less well-founded. We have concept art of the Valhalla space station and the escape pods from it, the latter of which can be found in both the Manhattan map assets and in the released DOOM game from 2016. It’s possible that the story was going through revisions and this is a middle ground between the original DOOM 4 premise and what would become the early premise for the reworked game. It is also possible both of these stories co-existed, either with the player starting in space before going to Manhattan where the hellwave event took place or perhaps as two separate perspectives of the same campaign - one from a civilian and one from a marine.