The Doom games have never had the most intricate or detailed plots. The originals laid out a bare bones premise that served merely as an excuse to kill demons, and at no point did they attempt to develop the hero, the universe, or the mythology. Doom 3 was the only game to tell a story in any sort of cinematic sense. Doom 2016 appears to be a mix of the two styles. All that is known about the story at this time is that there is a cult attempting to weaponize the demons (always a good idea), and there is a character named Dr. Olivia Pierce who appears to be their leader. Of course, all that matters is that there are demons in space and you need to kill them all, and this serves as a good enough premise, although there is sure to be more. Id Software has also stated that the story won't be presented using cutscenes, and instead will be told in real time as you play. This is the right direction, as it suits the style of Doom by keeping the player focused on the action. Other than these facts, the developers are keeping their lips sealed in regards to the plot, in all likelyhood because it doesnt really matter that much. But who knows, the story could surprise us.