Fallout 76 is a new game in the Fallout series, taking place 200 years before the main story of Fallout 4, and will take place in a totally online environment for players to explore the area of Appalachia in Virgina. Players can build bases anywhere on the map, and accessibility to nuclear weapons allows anyone to access missile silos and fire a missile anywhere on the map. These irradiated areas will contain rare weapons, gear, and items, but there's also an added danger in the enemies that can be found within.
The game will have no human NPC's, instead relying on a combination of robots, holotapes, terminals throughout the game world, and environmental storytelling to allow the player to piece together the fragments of narrative. According to Todd Howard, Bethesda wants players to get pieces of the story from the game, while also giving them the ability to create their own narratives.
Here's a bit from the developer:
Bethesda Game Studios, the award-winning creators of Skyrim and Fallout 4, welcome you to Fallout 76, the online prequel where every surviving human is a real person. Work together, or not, to survive. Under the threat of nuclear annihilation, you’ll experience the largest, most dynamic world ever created in the legendary Fallout universe.
Reclamation Day, 2102. Twenty-five years after the bombs fall, you and your fellow Vault Dwellers—chosen from the nation’s best and brightest – emerge into post-nuclear America. Play solo or join together as you explore, quest, build, and triumph against the wasteland’s greatest threats.