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In order to prepare for breaching the Vault, Meg needs an expert on heists. The problem is, Lucky Lou, her ghoulified expert, is nowhere to be found at Crater and the Residents will need to find him first and convince him second.
To complete the quest, the player character needs to first persuade Meg Groberg and her raiders to help get into Vault 79. Meg refers the player character to Lucky Lou, but she is not sure where he is. A cursory search of his room reveals a note that suggests Caleb Fisher may know where he went.
Speaking to Caleb reveals that Lou is missing. The player can use Charisma 8+ or Strength 8+ to persuade or intimidate him into revealing that he is deliberately throwing people off of Lou's trail at the ghouls' own request. He will give the player a tracking beacon which assists in locating the mine where he could be hiding. As an alternative, the player character may hack Caleb's level 3 terminal (Master Hacker required), in order to skip some of the legwork to locate Lou's actual last known location.
The beacon can be tuned into via the Pip-Boy's radio or the player may simply head south to Carleton Mine. Weasel is found just inside the mine and she will help progress deeper into the mine to find Lou.
At the first mine junction, Lou will speak to the player via the intercom. He will explain that he does not wish to talk or see anyone. To bypass the sealed gate, Weasel will offer to plant a charge and detonate a section of the mine wall in a dead-end corridor just off to the side; when that is done the player can proceed further.
Weasel and the player character happen upon a makeshift suicide machine: A chair and a shotgun rigged by Lou in an attempt to commit suicide. Near this chair are several structures and a mine shaft. The left branch of the mine shaft has a door but it requires a terminal to unlock, which is not in the immediate vicinity. Following the right branch leads to a bridge and a stairway, and then another intersection.
At this juncture is a single fog crawler, additional structures, another suicide device (a button wired to several automated turrets), and a door that can be opened with a terminal. Hitting the red button in the center will activate the turrets and cause them to attack the crawler, after which they self-destruct.
That passage leads past a third suicide device, a wooden structure. The area shakes as though the mine were collapsing and the ceiling, studded with threatening spikes moving downward. However, before they crush them and Weasel, the floor collapses and they fall through, into a pool within a cavern.
After falling into the cavern's pool, exit and use caution nearby, because radscorpions inhabit the cave. They can be spotted from afar near radscorpion egg nests, as the cave is dark and linear. Once the final radscorpion has been killed, Weasel will locate another weak wall and blow through it.
Past that lies a large area, with an open chamber, a waterfall, and the location's steamer trunk. Down the main corridor stands Lou is in the middle of placed explosives. Weasel will suggest a stealthy approach to disable the explosives before Lou will realize. If stealth does not succeed, Lou will be willing to talk face to face about his situation.
The player character will need to convince Lou to not commit suicide with explosives. Listening to Lou's story and explanations, and choosing dialogue options to confront Lou's fears makes him doubt himself if he will truly turn feral and become a risk to others. Along with convincing Lou, he asks for a deal made to help him kill himself after the heist is done. The player character may reply in a neutral manner so that Lou keeps his suicide idea in mind, even if the player is hesitant to accept his proposal.
Alternatively to just running up and speaking to Lou, the player character can sneak around and disable all the explosives in the room flipping the four circuit breakers in the room by following the red wires to each of the breakers. Doing this, the player character can tell Lou about the explosives being disabled and how they just want to talk or goading him into trying to explode the mine only for nothing to happen. Either option continues to recruiting Lou for the Vault 79 job.
While speaking to Lou near the end of the dialogue tree, mentioning the details of the job instead of keeping the details withheld for later seems to improve Lou's disposition and willingness to help with the Vault 79 heist. Once the player has finished speaking with Lou and has convinced him to not commit suicide, all they need to do is return to Meg at the Crater to finish the quest.
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