once you enter the vault the protocols are activaited and your stored in you cryogenics tube along with all the rest of your 400 some fellow vault dwellers and cryo sleep is initiated where you will sleep for a thousand years?......... maybe!
During the time your sleeping several events happen in the wastelands of the U.S. the master is defeated by the vault dweller,the oil rig that the enclave controls is destroyed by the chosen one and their base at navarro is over run by the ncr setting off the rise of the super power of the new California republic, the east coast enclave (remnants of the west coast enclave) establish a base at the ravens rock facilitate which is eventually wiped out by the lone wanderer and their base at Adams air force based is wiped out by the east coast brotherhood of steel chapter (known as the pride other than the brotherhood),and finally, but not least the courier decides the out come of the battle of Hoover dam (depending on his choice it effects the Mojave wasteland accordingly). the game would be set 4 years after the events of hoover dam and it would continue the story some what of fallout 3 but in the end it would have its of unique flavors to provide.