Strictly Business

Strictly Business is a side quest in Fallout 3. It is also a PS3 trophy and Xbox 360/PC achievement.

This quest will begin the first time the Lone Wanderer approaches Paradise Falls.

Grouse will address the Lone Wanderer and tell them that they cannot enter Paradise Falls unless they have business there. He will offer to let them in only if they go and enslave select people from his "VIP list." The Lone Wanderer will be allowed into Paradise Falls after they have enslaved at least one VIP.

This quest involves the Lone Wanderer enslaving several characters for the slavers of Paradise Falls. Enslaving is done with the Mesmetron and a slave collar, which they will get from Grouse. Along with it comes the slave collar instructions and list of "recruits" for Paradise Falls as well as the holodisk Mesmetron manual - summary page. Make sure to return to Grouse after each slave to collect a new slave collar for the next one.

VIP List
The characters that have to be enslaved for the slavers are the following:
 * Flak from Rivet City.
 * Red from Big Town.
 * Susan Lancaster from Tenpenny Tower.
 * Arkansas from Minefield.

If Red, Susan, or Arkansas are dead before the quest is given, they will not appear on the list and Grouse will allow the Lone Wanderer to enter Paradise Falls.

Arkansas
Arkansas is sniping from a ruined building in Minefield. One should be careful as they make their way through the town, as land mines are scattered all over the town. Arkansas will also snipe and shoot at cars, which can explode and kill the Lone wanderer. Once he is collared, mind the mines for him as he starts running for Paradise Falls (fast travel is an option).

Susan Lancaster
Susan Lancaster may be found on the third floor of Tenpenny Tower in her suite (at night). Simply shut the door, mez, and collar. If the Lone Wanderer has found the note left in her room revealing the possible affair between her and Edgar Wellington II, they can show it to Millicent Wellington. Millicent will kill Susan and she will not have to be enslaved. If Susan is the Lone Wanderer's last target, the quest will be completed as soon as she dies.

If Susan is enslaved while others are present, then the whole tower will be on alert and come after the player character with deadly force. Try to do it discreetly, or follow the note and affair scenario.

Red
Red can usually be found in her clinic. If she's not there, try walking around a bit and then enter her clinic again. If one did not complete the Big Trouble in Big Town quest yet, Red is captured by super mutants and held in the Germantown police HQ. One can simply enslave Red there, but it will prevent them from completing the quest unless they rescue her from Paradise Falls later. It is possible that she will get killed by a super mutant attack after completing Big Trouble in Big Town and she will not have to be enslaved.

Flak
Flak can be found in his room on the Upper Deck at night, and is probably the most difficult VIP to capture. He will sometimes appear alone, though outside his room, walking to or from his shop.

Bugs

 * If one enslaves and orders a victim to go to Paradise Falls, and then die/reload previous save, the character who was enslaved before reloaded the save may appear in the Paradise Falls slave pen, without a slave collar on, and with all of the dialogue options they normally had (for instance, one can still trade with Flak in the slave pen if he does not have a slave collar). Reloading the save will not fix this problem every time, so one may have to somehow get the target to come near them in the slave pen where the player is able to mesmerize and fit a collar onto the target. If Arkansas was the target, he will pull out his sniper rifle and begin shooting everyone around him.
 * When mezzing a person in V.A.T.S. with the Mysterious Stranger perk active, the Mysterious Stranger may appear. The Mysterious Stranger will look and move around, but no gunshots will be fired. If there is another enemy close by, however, the Stranger will shoot them instead.
 * One may be able to get paid multiple times for each of the VIP slaves captured. After getting paid the normal money when one reaches Paradise Falls, they can pickpocket a key to the slaves' pen. After talking to each of the VIP slaves that have been captured, return to the Paradise Falls entry and talk to Grouse and collect the 250 caps reward for each VIP slave spoken to in the slave pen. Grouse will repeat his speech as if they had just captured one of the slaves. If one finishes the dialogue with Grouse and speaks to him again he will then repeat his speech for one of the other VIP slaves spoken to in the slave pen. This can be repeated by talking to Grouse for each VIP slave spoken to in the slave pen collecting the 250 caps reward each time Grouse is spoken to for a total of up to 1000 caps at a time if one has captured and spoken to all four VIP slaves. It is possible to repeat this glitch for an unlimited amount of caps.
 * If one enslaves Flak, Shrapnel may disappear from Rivet City. He will return only once in a long while (every few days/weeks). He can be seen wandering the wastes and even in Paradise Falls likely looking for Flak. All dialogue will be normal as if he was still in Rivet City selling goods. Apparently, Shrapnel's wandering after enslaving Flak is caused by an AI script that says the two should sleep near one another. Enslaving Flak thus causes Shrapnel to wander the wasteland trying to get to him. This also works if you enslave Shrapnel.
 * Sometimes, everyone in Rivet City will turn hostile when enslaving Flak. If the player character dies in the encounter, Flak will wander the wasteland when the save is re-loaded. All dialogue will be normal as if he was still in Rivet City selling goods. This will usually cause Red's removal from the quest list and all people of Big Town will be found in a pile dead with only the robot roaming around.
 * If Red is enslaved right after they freed her from the prison and fast travel to Paradise Falls, it will complete the task "bring back Red to Big Town" and "enslave Red from Big Town" at the same time, if Strictly Business and Big Trouble in Big Town are both quests in the Pip-Boy. However, after fast traveling back to Big Town, one can see Red on her way to Paradise Falls, one can remove her slave collar and then ask for their reward for bringing her back to Big Town.