Stage 1: On completion of 'The Silver Shroud' quest, Irma, owner of the Memory Den, will appraise you for your bravery and for saving her dearest customer, or grieve with you at the loss of said customer. However, in all cases she will flirt a little with you, noticing how well you handled yourself throughout the quest. This will lead to her mentioning some rumours about a series of holotapes containing algorithms for novel, psychedelic memory lounger experiences. Obviously, at this point, still in her flirtatious mood, she will ask for you to retrieve them. Irma will point out that she had previously hired a gang of Gunners to find the holotapes, only one (Hannah McCarthy) of which survived the journey. She will point out that this ex-raider was last holed up at Harbormaster Hotel with other Gunner-defectors/runaways. She will also point out that the Gunners had given her a copy of the map they where using, which pinpoits the location to Vault 117, a submerged Vault located just east of Boston Airport. You now have two choices, go and find the ex-Gunner and figure out if they can give you information about the location, or head straight to the Vault.

Stage 2 (Optional): On arriving at Harbormaster hotel a Sniper will fire a round hitting a mailbox just beside you, the Sniper being located at the roof of the hotel. They will tell you to stop and hold your position as three or so raiders leave the fortifications and surround you. Here you are given a series of dialogue choices where you either engage them in combat and fight your way in to Hannah, or you trick them into believing you are an ex-Gunner (easier convincing if you are wearing Gunner Armour, and requiring high charisma) allowing you to freely enter. In either case, bringing up Hannahs name will result in them laughing at you and telling you that they have her caged up after she had been caught stealing Jet from the gangs stash.

When you get to Hannah you must convince her to tell you about Vault 117, however, she is terrified fo the place and has bad memories of it. As such you must find a way to get her to speak... You can torture her using some electric shock therapy (High Perception required, screen will black out), you can smooth talk her (High Charisma), you can heal her (Medic), or finally you can free her (kill everyone, or convince them to let her go for a high price). When you convince her to speak she will tell you that the vault had a cave in where you can swim in instead of walking in the entrance where two Legendary Sentry Bots wander around, she will also give you the locations of her ex-comrades, and tell you that they all turned on each other and hid in their own rooms, finally she will inform you of her escape route. After doing so you can offer her a job (assuming you free her, requiring high charisma/lots of cash/killing everyone, this will also be easier if you use the Medic perk, and is impossible if you torture her) where she will act as a Level 4 Weapon Merchant, and will stock unique grenades (+ she will give you the recipe, this may also be obtained by torturing her).

Stage 3: If you spoke with Hannah you may opt to use the underwater entrance where the lower levels of the vault have been flooded, note you will most likely need Aquaboy or a rebreather. Otherwise you must go in through the main entrance where two Legendary Sentry Bots are patrolling. Once you get in you will notice a series of Screens in every room and hallway replaying the same message from Braun mocking the Gunners with their personal details. However, as you begin to venture deeper into the the Vault the insults will change from him mocking now dead Gunners, to mocking personal details about yourself and your companion (Strong for example will be mocked for wanting to make Super Mutants better, and will be told their race was doomed, resulting in him smashing things around him).

If you spoke with Hannah you will find the locations of the previous gunners who each hold some great loot, and the leader (who looks as though they have shot themselves sitting in the Overseers chair) will hold a unique weapon.

Eventually you will get to the center of the vault, which will feature a configuration similar to the one found in his own Vault back in FO3, and inside the pods are skeletons. Going to the terminals located in the room on the other end will point out that this is a vault centered around EEGs and other brain scanning tech which brings out your memories for it to read, which Braun modded to use as a tool to mock the residents and enrage them. This resulted in various Vault dwellers murdering each other mercillesly, the overseer being the first to get murdered by the Vault Doctor, who decided to perform experiments on the overseers brain (his personal terminal will inform you that the Vaults effects resulted in his dreams being about his failed neurosurgery practice, and the patients who died in his practice before). Other examples of murders are strewn all around the vault, from a daughter murdering her mother because she loved her brother more than her, to jealous school students murdering each other because one recieved higher grades than the other.

You finally find the tape Irma needs in one of the computers, and the terminal readings will explain that these holotapes cause memory-lounge users to become wildly jealous, paranoid and murderous. The moment you pull it out a new recording will appear on the screen with Braun reading out a failsafe for the programme being ended abruptly, and a series of robots will be released into the vault to look for you (psychotic Mr. Handies and a few Medic/Fire Protectrons). If you spoke with Hannah you will realise that the vents behind you can be traversed and will take you to the lower levels where you can swim out again. Otherwise, fight through and exit.

Stage 4: Return the holotapes to Irma. When you get back to Irma she will be in Dr. Amaris room discussing something. You can try to explain what happened, and if your Intelligence is 7+ you will pass a check with Dr. Amari confiscating the tape, if your Charisma is 7+ you will convince Irma that the tape is dangerous, and she shouldnt upload the new firmware to the pods, otherwise they will ignore your advice and upload it anyway. If uploaded you will return later to find Goodneighbour are barring entrance, and if you get in you will find everyone dead except Connolly who is stuck in his lounger, a guard is waiting for him to come out for questioning. If you do succeed in the former two options Connolly will steal the tape and will end up on his own stuck in the Lounger leading to a new quest (no dead people, just Irma very worried that Connolly has been stuck for a while).