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One needs to 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, but he will give one a tracking beacon which assists in locating the mine where he could be hiding. Optionally, 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. Upon entering the mine, one will encounter Weasel, who will help progress deeper into the mine to find Lou. Weasel can plant a charge and explode a section of the mine wall; when that is done the two of you can proceed further.
An intercom connects to Lou, who doesn't want to talk to you.
Weasle and the player character happen upon a makeshift chair and shotgun device that appears to have been created 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 fog crawler, additional structures, another suicide device (a button wired to several automated turrets), and a door that can be opened with a terminal.
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. If the player character is not careful, the floor collapses and they will fall through. Falling down into a pool within a cavern.
After falling into the cavern's pool, exit and take caution of the nearby radscorpions that 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, enter the large area past an open chamber with a waterfall, down the main hallway where Lou is in the middle of placed explosives at the farthest point in the mine. 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. 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, return to Meg at the Crater to finish the quest.
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