Trouble on the Homefront

 is a Fallout 3 quest. It is also an Xbox 360 and PC achievement and a Playstation 3 trophy.

Objectives and walkthrough
This quest will be activated anytime after completing The Waters of Life quest (which is part of the main storyline) by picking up the Vault 101 Distress Signal on your radio. To pick up the Vault 101 Distress Signal simply wander near Vault 101 (Megaton is close enough). It is a message from Amata asking you to return to Vault 101 to help stop her father, the Overseer. If you killed the original Overseer while escaping from Vault 101, Allen Mack will be the new Overseer and you can still do this quest (although the radio message changes to "...the new Overseer is insane, you have to stop him").

Since you and your father escaped from Vault 101, the Vault has been fractured into two major factions. The faction led by Amata, holed up in your father's Clinic, wants to open the Vault and interact with the outside world. The other faction is led by the Overseer and he wants to keep the vault closed permanently, in accordance with its mission. A few of Amata's rebels, notably Butch, want to abandon the vault entirely and live on the surface; the majority, however, intend to remain living in the vault but want to be able to make excursions into the wasteland when necessary.

One of the most essential reasons for having access to the wasteland and the remainder of humanity, apart from the obvious need for supplies and parts for the vault's aging life support apparatus, is to avoid collapse due to genetic stagnation and inbreeding - the number of vault 101 residents has fallen significantly in the two centuries since it was sealed, implied heavily by various conversations and other means (such as a message encouraging procreation on the text messagers) prior to the lone wanderer's initial escape, and if he successfully persuades the overseer to allow exterior access then the overseer himself will finally accept and openly admit that without external input, the vault's population will not remain genetically viable for more than a generation or so.

Solutions
Although there are only three markedly different outcomes, there are plenty of ways to finish each. Be creative!

Keep the Vault Closed

 * Simply ignore the radio message. The signal will cease after awhile and you will lose the opportunity to gain xp and the Modified Vault 101 Utility Jumpsuit.
 * You can also just enter Vault 101 once, talk to some people and/or take items (such as opening the safe in your father's office) and then exit the vault. After leaving, you will be unable to reenter the vault as it has been locked again.
 * Kill the rebels. Killing only Amata should break them up, but you may also have to kill the other rebels as well.
 * Persuade Amata to stay in the Vault (using Speech).
 * Hack the Overseer's computer and discover the attempts by the Enclave to gain entry into Vault 101, and the Overseer's refusal to admit them. Speak to Amata and tell her this and it will convince her to stay in the Vault. This has the same result as Speech, but without the skill check.

After convincing Amata to keep the Vault closed, you may talk to the Overseer who will ask you to leave. If you ask him about a G.E.C.K. he will tell you that Vault 101 never had one and will offer you the Modified Utility Jumpsuit instead. Alternatively, you can ask him for food and ammo to get 15 Cram (with no radiation) and 350 5mm rounds in place of the suit.

Open the Vault

 * Kill the current Overseer.
 * Persuade the Overseer to open up the vault, using Speech. NOTE: This will only be available if Alphonse Almodovar is still the Overseer.
 * View the computer in the security office either by hacking into it or obtaining the password from the desk or Officer Wilkens. Then inform the Overseer of Security's plans to kill the Rebels. Similarly to Amata, this is a guaranteed way to achieve this outcome (as long as Alphonse is Overseer) . You can also learn of the plan from Mr Brotch after releasing him from the cell.
 * Discuss with the Overseer about why the Rebels are correct. By using a Speech skill check, he will realize that the Vault won't survive more than a generation or two no matter how many supplies they may receive.

Amata will take on the role of Overseer - if her father is still alive, he relinquishes the role. If you talk to her she will then 'ask' you to leave the vault permanently and will provide you with the Modified Utility Jumpsuit. You may randomly encounter Vault 101 citizens in the Wasteland (on trading or scouting missions); talk to them and they will give you purified water but say that you still cannot return. Butch will end up in Rivet City at The Muddy Rudder.

Destroy the Vault
Hack the (Hard) computer in the sub-basement or steal the Vault 101 Utility Passcode from Stanley, the maintenance man, who can be found wandering around the cafeteria/dorm level. Go into manual override mode and perform a flush and a purge. This will flush the water chip. Everyone is forced to evacuate the vault and you will see them spread out in the Wasteland (you lose Karma for this). This is always an option - you can even complete the quest with another method and then flush the chip, although this will render anything you did before meaningless from the quest's point of view.(NOTE: This option is no longer available with the latest patch.)
 * The passcode only unlocks the terminal and does not enable you to unlock any extra areas of the Vault.
 * You can lie to Amata that it was the Overseer's plan, or lie to the Overseer that the rebels did it. In the latter case he will stay where he is, ashamed at what he has caused, which results in his death.

Obviously, life in the vault is no longer feasible. A random encounter may occur where Amata is being interrogated by the Enclave. If she gives up the location for Vault 101, she will be executed. If you save her life she runs away from you, cursing you for all the trouble you caused. She doesn't have a destination and will eventually be killed by one of the horrors of the wasteland. Other Vault 101 members will be scattered throughout the Wasteland as well and will unsurprisingly be hostile towards you. Freddie Gomez can be found dead near the Deathclaw Sanctuary (confirmed).

Doing this nets no rewards of any kind except bad karma; if you particularly want a reward then you can complete the quest that way, get the reward, and then destroy the chip. You can of course still loot the Vault - it's not like anybody is going to need it afterwards.

Failure
Not just evil, but a complete psychopath? There's an option for that too! Killing the overseer after getting the vault either open or closed results in failure of the quest itself. They also cause the Vault to be left open and you can come and go as you please, but all residents will turn hostile. A message will appear explaining that Vault 101 has been 'thrown into chaos'. If you decide to make it a home-away-from-home, be aware that even after you've killed all the people, the place will become infested with radroaches.
 * It's possible for this to happen accidentally - if you convince the rebels to stay and then go to the Overseer when Officer Wilkins is nearby he will cause the Overseer to become hostile as well. This won't instantly cause failure unless the Overseer actually dies.

Glitchy Endings

 * It is possible to kill the leaders of both sides without failing the quest. Resolve the situation, killing people if you want, but spare the acting Overseer (whether it is Amata, her dad, or Mack). Attack the Overseer and make them pursue you to the entrance of the vault but don't kill them. After the vault door closes and the quest is deemed completed, you can delve in the joy of slaying the previously "critical" NPC and get away with it. You won't receive the message about the vault being thrown into chaos if you achieve this.
 * It is also possible to finish the quest and have the vault door stay open indefinitely. Enter the vault and don't talk to anyone - ignoring Officer Gomez, Amata and the Overseer is critical but there's no real point in talking to anyone else (except perhaps Butch, to get the optional "Sabotage Vault 101" subquest on your Pip-Boy, but it isn't necessary). Head to the reactor area and purge the water chip. This will cause the vault to evacuate. Wait about 2-3 minutes realtime (waiting should work?) and then go through the Overseer's tunnel. (If you can't avoid the Overseer here, lie to them.) Leave the vault when it says the quest is completed (when the vault door would normally close). The door will remain open forever, and the vault will be empty of people.
 * Does closing the vault door lock it? Method above not confirmed.
 * If you avoid the Overseer when leaving they may remain in the vault, alive and with no dialogue options.

Bugs

 * It has been reported that Butch could appear in the Muddy Rudder in Rivet City even if this quest is resolved in such a way that would preclude his appearance in Rivet City. (This includes convincing the rebels to stay, or even killing the rebels)
 * On the PS3 version many people have experienced the game completely shutdown whilst exploring the vault and exited to the menu. It's a constant bug during that whole section of the world map.
 * On the 360 and PS3 version I have encountered a different bug, I was fooling around and kept going back to a previous save game, when I went to go again I was unable to pickup the frequency, disabling me from getting the password for the vault door which is Amata. This is before patching to 1.10.
 * When you get done talking to Amata she followed me outside the vault. When the door closed she ran against it trying to get in.
 * When officer Gomez tells you to wait where you are, run forward and go to Freddie, behind him there's a door he runs into, but if you follow him it gets blocked up, so run in there before he does. He will get shot at and run into the door where you are, but the then will suddenly disappear. Leave the door and enter again to see that it's been blocked up with lockers and tables
 * If you killed Amata's father and Mack is the Overseer, it is still possible that you may hear her tell Mr. Brotch "My father would never allow it" as he is talking to her in the Clinic.
 * If you convince Amata to stay, get your reward from the overseer, then kill the overseer, it will say caution as if someone seen you. When you leave the vault, it will still say caution and stay like that.
 * You can get stuck in between the power coils in the sub-level of the Vault.
 * In my playthrough I had Dogmeat and Charon stay in my megaton house, I told them to wait there, I did the Trouble on the Homefront quest and when I went back to my house they were both gone, but a few days later it said Dogmeat iswaiting for you outside of Vault 101, and a few days after that it said Charon has returned to the ninth circle
 * If you do not kill Officer Wilkins after he becomes hostile, he will try to find you throughout the Vault. If any Vault citizens see him as a hostile against you, they will also join in the fight to kill you. I discovered this glitch after I let him be. I chose to warn Amata about the Enclave, and she accepted it. I was on my way out when Officer Wilkins started shooting me. Then Butch, and a few other people joined in to kill me.
 * If you enter the operation anchorage simulation when the signal was available but not activated the quest, the signal will disappear upon exiting the simulation preventing you from ever starting the quest. There was an unusual fix to this however, when exiting The Pitt, the signal becomes available after returning to the capital wasteland.
 * If you convince Amata's father to step down as Overseer while she is asleep, he will run to the rebel base and begin his resignation speech over her sleeping body. She will shout out her lines normally, although will remain unconscious the entire time.  After the Overseer finishes, he will leave, as normal.  Amata will not wake up at this point, unless either her scheduled wake-up time is reached, or if you speak to her.
 * If you went to Republic of Dave, the son of Dave, Ralph, will appear in the Vault. He'll be fleeing the time he's there. This is unknown if it's on the PS3, Xbox 360, or PC.
 * If your follower kills the overseer they get stuck in the vault door exit on the way out and dialogue will not be able.Sometime later you will get the message saying they have died.(works on charon ,rl3 and clover)
 * After completing the quest by helping the rebels, Three Dog's radio broadcast goes as far as "Who says you can't go home again, children? The kid from Vault 101 did." before switching to another, different radio broadcast, i.e. Grayditch going "quiet", et cetera.
 * If you find the Overseer in the room with the security guard that becomes agro to you after he tells you he will make sure no one else ever leaves the Vault, the Overseer will assist and attack you. Simply reload until the Overseer spawns in his office to avoid this.

Fallout 1 Reference
Some of Amata's speeches to the player when they leave are strikingly similar to the speech given to the Vault Dweller at the end of Fallout (bold quotes specifically).