The Nuclear Fallout (Based on Fallout 3)

Note: My story is based on the post-apocalypse video game named Fallout 3, though I changed and added a lot of my own stuff

Foreword
War. War never changes. Since the dawn of humankind, when our ancestors first discovered the killing power of rock and bone, blood has been spilled in the name of everything: from God to justice to simple, psychotic rage. A nuclear bomb affected the whole planet Earth, making the world an unsafe place for people. Houses, towns, cities all destroyed... Ruined. Blown to pieces.
A co-operation named Vault-Tec was responsible for making underground vaults for a "safer place for people to stay and live" during the Great War. When people thought the war was about to finish, just then... Just then the bomb was dropped. That was 200 years ago. People named the event" The Apocalypse."
The vaults are still in use. They were and still are dreadful places. Metal corridors, after metal corridors, under the ground. It feels like living in a metal cage. Even though the vaults are nothing better than death camps or prisons, thousands immigrated to the vaults for a chance of survival. What used to be a dreaded place is now considered salvation.
Thus, our story begins.