The vault was intended to encompass two wings under one overseer, one to house members of the highest class of society (Hollywood actors, business tycoons, scientists, artists, etc.), while the other to house the lower classes. The second wing was never finished and while the vault was used as a fallout shelter, the vault experiment never started.
Vault 118 was primarily built and intended for housing upper and lower class citizens, in order to test what would happen when the two groups clashed. However, after the luxury wing was completed, funding for the project stopped and construction for the lower class wing was halted.
Apart from a few scientists, the only other Vault-Tec employee was the overseer, with all the servants being robots, in order to minimize conflict on the experiment.
After the vault was closed, Bert Riggs, a former scientist at General Atomics International proposed to move the inhabitants' brains into robobrains in order to survive longer. All inhabitants and senior Vault-Tec staff agreed to this, against the protests of the overseer. Shortly after, the Overseer was driven mad by the robobrains and committed suicide.
Upon entering the lower level of the hotel, the vault entrance will be found with the door sealed. Activating the door controls will trigger a conversation with Maxwell, who asks the player if they are the detective he requested. Answering yes will open the door. Maxwell will be waiting for the player in the front entrance. If Pearl is present due to recruiting the player as the detective and escorting the player, she will interject and answer instead.
Going right leads to an extremely lavish hallway with a large fountain. Straight from the fountain leads to the ballroom, where the murder took place. Right from the fountain goes to either Pearl's shop on the right, or residences ahead. This residence hall contains a room full of display cases containing various items attributed to Ezra Parker's pre-war exploits, which leads to Ezra Parker's bedroom; Keith and Gilda's stage, with their adjoining bedrooms; and the classroom, which functions as Bert Riggs' lab and contains several tools and a chemistry station. A staircase at the back of the hall leads to the upper level.
Going left from the fountain, the player can either go left into the security office housing four protectron charging stations, a desk, and a staircase to the upper level, or right leading to another hall of residences. This hall houses Santiago Avida's art gallery, next to it is a decrepit bedroom that appears to belong to Santiago, though it appears he never uses it. Across the hall is Julianna and Bert's room (filled to the brim with assorted junk) and at the end of the hall is the showers. Beyond the showers is the beach, with sand and an artificial lake.
Going left from the main entrance is a short hallway filled with trash that leads to a sort of parking garage. A Corvega is suspended from a crane surrounded by nine garage doors on either side, three doors to a level. The large vault elevator, similar to that of Vault 111 and seen on the surface outside the hotel, can be found here. A hole in the wall on the center garage, second level right side, leads to a small cave with a bulldozer and crates. Beyond that is another small room with a door blocked by crates.
The upper level of the vault is in complete disrepair as opposed to the lower level. The overseer's office is found upstairs in the right corner of the ballroom. Inside, a desk takes up most of the main room and contains the skeleton of the overseer, which is wearing a Vault 118 jumpsuit, and the overseer's terminal next to him. Behind the desk is an entrance to the overseer's personal quarters, with a lavatory. The only other location upstairs is the Hydroponics lab, across the ballroom from the overseer's office. A variety of plants can be found here, as well as at least one Concierge attending them.
- Fencebuster, a unique blue baseball bat that can be found in the middle hall.
- The Dapper Gent, a unique formal hat that can be purchased from Pearl.
- Vault 118 jumpsuit, inside the vault, to the left on the counter, close to the entrance, where the residents would get their own.
- Vault 118 overseer's log - on the overseer's terminal in his office.
- Vault 118 overseer's key - In Ezra Parker's room. Opens the door to the overseer's office.
- Request for detective - Carried by Pearl.
- Road goggles inside a locked display case in the room flanked by lion statues.
- Clean salt shaker, pre-War variant only found here, behind Pearl.
- Cat remains, uniquely named vases in the Riggs' room.
- A red paint can.
- A pirate hat can be found on a bust in the "museum" room with the two lion statues at the entrance.
- Four plastic skulls in a locked display case in the same room as the pirate hat; these are the only known plastic skulls in the game.
- Letter to Ezra inside a wooden console in the recording studio; unlocks a moderate persuasion check with Gilda Broscoe and Keith McKinney.
- Brain Dead: The Sole Survivor is contracted by Pearl or Maxwell to help investigate a recent murder.
- Except where required for the Brain Dead quest, the NPCs in this vault cannot be killed. Causing any of the robots to become hostile will cause all of the robots to become hostile, but they will always replenish their health instead of dying. However, once the mission is completed, the NPCs can then be killed.
- The vast majority of items in the vault count as owned and need to be stolen, should the Sole Survivor wish to acquire them.
- Vault 118 is the first ever vault to make an appearance in an add-on expansion.
- The water of the artificial beach is radiation free to stand in, but bottling it in survival mode still gives dirty water.
- The player character may use any bed to sleep.
- If the player character kills Pearl, none of its inventory is available to loot.
- Despite usually being opposed to stealing, Piper may quip that the hotel's wealthy inhabitants arguably would not miss some of their "nifty tech" while exploring the vault. However, she will still lose approval if the Sole Survivor appropriates owned items.
- The resident robobrains with the exception of Ezra Parker are the only non-homicidal robobrains in the game, and the only ones aside from Jezebel that can be talked to. While still comparatively sane, they are either in denial or unaware of the fact that the war they wanted to wait out lasted only a few hours and ended two centuries ago. There is no option to tell them.
PC Playstation 4 Xbox One Upon leaving Vault 118 via the elevator, the player may get stuck within the elevator. Reloading a previous save might help, some report that attempting a fast travel plus a few minutes wait time in the elevator fix it. Hearing elevator music upon loading may be an indication that you are no longer trapped.[verified]
- An alternate fix is to press the 'Activate/Call' button for the elevator even if the elevator is at the basement level with the door open. Close doors, press the call button and then proceed to take the elevator as usual.[verified]