This is a draft:
It was 30th August 1912, that fateful day when the atomic bomb unleashed its devastation across the globe. People had to live in vaults to sheild themselves from the heat, harmful radiation and the toxic gas. On that fateful day a child is born.
The prophecy has stated that a man will free everyone...
And that's how much I got. I think I still need to develop it a bit more but I was thinking that I won't tell the player too much but give the info in the game.