You wake up from cryogenic suspension and realize you’re in a vault. You’re immediately put onto a rickety conveyor belt with other dazed vault dwellers. If you listen in you can hear them start to talk about the war with the Chinese, last night’s baseball game, and other pre-war topics.None of them know that over 200 years have passed.
There are Vault-Tec robobrains patrolling around making sure everyone stays in line. You could chat with the person in front of you if you want, giving you a chance to explain who you were. You could also just say you don’t remember. After a while the conveyor belt will stop and a pre-recorded voice will announce that everybody has been woken up to be drafted into the U.S (Enclave) Military! And that after 206 years half of the U.S has been reclaimed and that they are to assist in reclaiming the rest of America.
(btw I’m aware that the enclave is gone now, this is just a pre-recorded voice that probably projected the Enclave would have been more successful.)
You are then put into a training area where you get your Pip-boy and learn what V.A.T.S is and the controls for Fallout 4. The walls are made of glass in this room so you can see the other peoples progress, and they’re all getting slaughtered by the training robots. You notice some of them weren’t even given guns. After defeating a couple of robots you go to the next room to learn that you are the only survivor or the training and are given an Enclave Officers uniform and a 10mm pistol. You would then exit the vault and to the nearest enclave base marked on your map. The base has been converted to a small town like Megaton or Goodsprings where the actual adventure would start.