From the introduction:
In the year 2077 the world would be forever changed, as atomic hellfire rained from the skies all over the world; a short-sighted attack that would send humanity to the brink of destruction. But this would not be the end of humanities’ struggles, as life would adapt, mutate, reemerge, and reinvent itself. You will start out on October 23rd, 2286; one year before the awakening of Vault 111’s Sole Survivor. From there, you will lead your own life, making your way in the Commonwealth.