Vault 81 (quest)

Vault 81 is a quest in Fallout 4.

Detailed walkthrough
When the Sole Survivor arrives at Vault 81, they proceed to connect his/her Pip-Boy to the entrance button in an attempt to open the vault doors, however they are greeted by the present occupants of the vault, who are descendants from the original members of Vault 81.

The vault is one of the few that hasn't been captured or overthrown, and remains orderly and secure for the residents.

The Sole Survivor from Vault 111 is told by the overseer of Vault 81 that if he/she wants to enter their vault, they need to bring 3 fusion cores as means of payment.

When having returned with the cores, the player character will be allowed to enter the vault, and Overseer Gwen will welcome them to the vault, and the Sole Survivor will be allowed to trade and interact with the residents of Vault 81. Overseer Gwen explains to the Survivor that although the vault can provide a lot of resources for themselves, sometimes they require outside materials to make sure the vault is stable.