Tenpenny Tower (quest)

Tenpenny Tower is a side quest in Fallout 3 as well as an achievement/trophy.

Quick walkthrough

 * 1) Travel to Tenpenny Tower and witness the ghoul discrimination outside of it.
 * 2) Offer Gustavo help with the problem.
 * 3) Kill the ghouls.
 * 4) Kill the residents and let the ghouls move in.
 * 5) Hash out a deal between Mr. Tenpenny and the ghouls.

Detailed walkthrough
Speaking with Chief Gustavo at Tenpenny Tower or Roy Phillips in the Warrington Tunnels reveals that a band of ghouls want to live in the luxurious Tenpenny Tower, but neither Allistair Tenpenny nor the other residents are willing to let them in. You can: kill the band of ghouls, let them into the tower, or find a diplomatic solution.

If you start with Chief Gustavo, you'll get an assault rifle and a promise of 500 Caps for the death of Roy Phillips and his "gang". A successful Speech check will raise your reward to 700 Caps, as well as upgrade the rifle to a Chinese assault rifle with some 5.56mm rounds. Attempting and failing the speech test means you will get a 10mm SMG instead.

Gustavo will direct you to the feral ghoul infested Warrington Tunnels southwest of Tenpenny Tower. Follow the tunnels and you'll find a door leading to Roy Phillips' hideout. Once you find Roy and his gang, you can choose to kill the ghouls, or offer to help Roy and his ghouls enter Tenpenny Tower through the secret underground entrance to massacre the residents of Tenpenny Tower, or find a peaceful way for the ghouls and humans to live together in Tenpenny Tower. One way the ghouls will take over and occupy Tenpenny Tower, and the other way the ghouls will be dead and the humans will continue living in Tenpenny Tower.

This quest will also be automatically added if you kill every resident of Tenpenny Tower. The quest will jump straight to the stage where you "Tell Roy Phillips the ghouls can move in."

Option: Kill the ghouls
The conflict can be easily solved by laying waste to Roy and his ghoul companions in the tunnels. After you kill Roy and his gang, return to Chief Gustavo and he will reward you with 500 or 700 caps, depending on whether you passed the speech check.

Option: Kill the humans
It is also possible to help the ghouls enter the tower by obtaining the key to the generator room from either Herbert "Daring" Dashwood or Chief Gustavo. To obtain the key, you can either pickpocket or kill Chief Gustavo, and may either pickpocket, kill, or choose certain dialogue options with Dashwood, including, 'I don't have time for games'. The door to the generator room is on the exterior of Tenpenny Tower around the back. If you kill all the humans in Tenpenny Tower then you can tell Roy that him and his ghouls can move in.

Option: Help the ghouls move in
If you wish to solve things in favor of the underdogs, talk to Roy Phillips about the possibility of a peaceful negotiation, then bring the proposal to Allistair Tenpenny. He will tell you that if you can convince tenants Edgar Wellington II, Millicent Wellington, Anthony Ling, Lydia Montenegro and Susan Lancaster to have the ghouls as neighbors, he'll let them move in. You can also get rid of the influencial tenants by murdering them to accomplish this task.

There are several methods of getting the five residents to cooperate. The first is passing a Speech check (for positive karma), which forces them to accept the change or leave. Alternatively, you can take the love letter from Susan Lancaster's desk and show it to Millicent Wellington; she will proceed to murder both her husband Edgar and his lover Susan. Millicent will then leave the tower, leaving only Anthony and Lydia. These two can be convinced to leave by stealing from their store safes and speaking to them after doing so.

Once all required tenants are convinced or otherwise removed from the picture, visit Alistair Tenpenny for a 500 cap reward. Once you bring Roy Phillips the news, he will reward you with a ghoul mask, which makes you friendly with all ghouls. You will also gain a 300 XP reward.

Upon returning to Tenpenny Tower, you will find human and ghoul residents living together. Inquiring among residents will indicate that both sides are getting along well. A few days later, however, all the human residents will be gone. Further investigation reveals that the human and ghoul tenants had a "disagreement", and that Roy Phillips decided to "take out the trash". The human residents have all been slaughtered, and their looted and stripped bodies dumped in the basement. Former residents of Tenpenny Tower such as Mr. Ling and Ms. Montenegro will also die and disappear at this point, even if they have moved to the entrance of Megaton.

Bugs

 * After you've let the ghouls move in using the diplomatic method and Roy killed the human residents, there are no body parts present and there are just a lot of blood stains. Sometimes a feral ghoul will appear and attack you on sight unless wearing the ghoul mask when entering.
 * The quest script that moves the ghouls into Tenpenny Tower will not check whether Roy is still alive before moving their bodies into the basement. So if Roy is killed before the human tenants are disposed of, he will still somehow manage to murder them.
 * Sometimes after letting the feral ghouls into Tenpenny Tower the assault on the towers residents will never end. If Susan Lancaster was sent to the slave pens, attempt to kill her in her pen then return to the tower and personally scour each level to ensure all residents are dead. After confirming this, talk to Roy and if he thanks you for your part in the siege, leave the tower, wait 24 hours and return and the tower should be functional again. An alternative solution to this bug is to kill all the ghouls yourself. Roy will not attack the player if he attacks the ghouls. After Michael Masters and Bessie Lynn arrive at the tower wait 24 hours and the tower should be functional.
 * If the "kill the ghouls" option is followed, the Tenpenny residents may occasionally give the player speech options indicating that the player had instead brokered the deal to let the ghouls move in. When starting conversations repeatedly, they may first greet you correctly (praising you for killing the ghouls), then incorrectly (as if you had let the ghouls in peacefully), then give you a generic greeting for all subsequent chats.
 * After you open the access door and meet Roy Phillips in front of the tower, he may not give you the ghoul mask. This bug appears to affect only players who have started Strictly Business and have already enslaved Susan Lancaster. Killing her in the slave pen will not cause Roy Phillips to provide the ghoul mask.
 * After letting the ghouls invade, sometimes it will permanently lock you out of your Tenpenny Tower suite.
 * Killing Roy Phillips will complete the quest, but if you fail to kill all three, the remaining ghouls will move into Tenpenny and will still mention Roy Phillips, as if he were alive.
 * Sometimes, upon re-entering Tenpenny Tower (after convincing Tenpenny to allow the ghouls to live in the tower), all levels of the building will be completely devoid of all life. To solve this, reload a save.
 * If you enslave any of the Tenpenny security guards, then choose to unleash the feral ghouls on Tenpenny Tower, the tower will be stuck in the attack mode forever. The game tries to check if the security guards are dead; however, as they have left the game world, they are never counted as dead. The only solution is to load a save from before enslaving them, or to finish the quest peacefully instead.
 * If you kill Chief Gustavo, and then kill Roy Philips, the quest will be stuck with the objective "Report back to Chief Gustavo". The quest marker will still appear pointing towards the Tenpenny Tower.