Take it Back!

Take it Back! is the twelfth main quest $$ It is also an Xbox 360/PC achievement and a PlayStation 3 Trophy. It serves as the final quest in the main game unless Broken Steel has been downloaded.

Attack!
When the Lone Wanderer reaches the Citadel, Owyn Lyons will be briefing his daughter Sarah and Lyons' Pride, in preparation for an assault on the purifier. After informing them of the situation, Sarah's squad is mobilized to wrest control of the purifier from the Enclave. Liberty Prime is activated despite the objections of Scribe Rothchild, who demands it not be used and declares "...it's not ready for field tests, let alone live fire situations - the weapons haven't been calibrated, the navigation detection system is offline..." Despite his warnings, Prime is launched and used without any malfunctions.

To begin the advance on the Jefferson Memorial, one must speak with Sarah Lyons. Note that once the order to attack has been given the green light, all functions, and services in the Citadel will cease. All non-player characters will spout encouraging phrases such as "The purifier is as good as ours!" if spoken to. If the player character has anything to do in the Citadel, they must complete these tasks before commencing the attack.

Following the order to attack, Liberty Prime will be hoisted out of the Citadel on a crane, and the Lyons' Pride will follow it, along with the Lone Wanderer. Prime makes contact with the wall of the bailey on the crane, but it does not damage him. Once outside the Citadel, Prime will begin stomping his way to the fallen bridge, killing everything in its path. Liberty Prime will take down the photonic resonance barriers set up by the Enclave by walking into them.

Once on the bridge, the Enclave will attack Liberty Prime in full force with soldiers, vertibirds, and artillery, but the machine will successfully repel these attacks, aided by the Lone Wanderer and Lyons' Pride. Liberty Prime will subsequently clear the path to the Memorial. The Lone Wanderer and Lyons' Pride can come under attack from targets on a catwalk between buildings after clearing the bridge from the Citadel. Liberty Prime will continue carving his way through the resistance, past the irradiated metro, and onward to a second bridge. At the end is where Liberty Prime stops, and holds his position along with the rest of the Lyons' Pride, while Sarah Lyons and the Lone Wanderer dash inside the Jefferson Memorial through the gift shop. If one hesitates, a significant force of Enclave soldiers will be deployed nearby, either from the bridge or the catwalks around the memorial. Liberty Prime will destroy them. There is light resistance inside the gift shop, usually three or four Enclave soldiers.

The Rotunda
After entering the rotunda, the doors seals shut, with no way to leave. Colonel Autumn is waiting for the Lone Wanderer and Lyons inside, and locks the player character in dialogue. One has two choices at this point: After resolving the situation and heading up the stairs to the control room, a panicked Dr. Li will key the intercom: Project Purity has sustained severe damage in the battle and has become overloaded. It will soon self-destruct if the purifier isn't finally started, but the control room has become irradiated to the point of lethality.
 * Talk Colonel Autumn out of attacking with a series of difficult Speech checks. If Raven Rock was destroyed in the last quest, there will be the option to use an easier Speech check - one can also inform Autumn of Eden's true plans regarding the purifier. However, even with 100 Speech and 5 Charisma, the player character still only has a 50/50 chance of success. After conceding defeat, he will leave the player character to their fate. After this, Sarah Lyons will give a short remark on the player character's decision, depending on one's Karma.
 * Fight Colonel Autumn. The Colonel must be killed alongside his two bodyguards, two standard Enclave soldiers, one of which may be equipped with Tesla armor. It is possible to attack the Colonel and kill him before the dialogue begins, though the soldiers are still hostile.

Final choices
Those with Broken Steel installed have additional options in completing this quest, as detailed in the second decision option. Now, the game has the player character make one final decision: who will activate the purifier. The radiation levels are fatal once the purifier is activated, so whoever goes in isn't coming out (RadAway, Rad-X and Radiation Resistance have no effect on one's survival, as it is a cut-scene).

Decision 1: Sacrifice yourself or Lyons
One choice is that either the Lone Wanderer or Sarah Lyons must sacrifice their lives to get the purifier going and prevent the destruction of Project Purity. If one hasn't figured it out from James' notes and recordings, the purifier password is 2-1-6 (referring to the verse from Revelation which Catherine loved). If the player character follows James to the purifier when he first enters the Memorial in The Waters of Life, James points out the code and repeats the passage. One is supposed to infer it from James' dialogue about the Lone Wanderer's mother, and the picture hiding James' safe in the Vault 101 clinic. If one chooses to convince Sarah to do the job, the Lone Wanderer will tell her the code in dialogue. If one has the Broken Steel add-on, the player character's Karma will be raised by 1000 if they decide to activate the purifier themselves. Karma is unaffected if Sentinel Lyons or one of the player character's companions is sent in.

Without Broken Steel, if the player character chooses to sacrifice themselves, once entering the password they slump away from the purifier password panel. A statue of Thomas Jefferson is revealed inside the central chamber as it is purged. A series of still images recounting the player character's actions throughout the game is shown. The relevant section of ending video ends with Sentinel Lyons looking at a shining pile of goo at the control chamber's bottom - which is, presumably, all that is left of the Lone Wanderer.

Contaminating the water (Optional)
If one chooses to activate the purifier themselves, this is the time to insert the Modified FEV created by President Eden into the water filter, assuming one wishes to and did not give it to Elder Lyons. As in Fallout 2, the only creatures spared by the modified FEV are pure strain humans who are still within vaults and the Enclave. This would reverse a great deal of genetic damage done by the nuclear apocalypse but at the cost of complete eradication of nearly all life on the wasteland. This decision is actually listed in the player character's Pip-Boy 3000 as a separate quest called Project Impurity; however, it cannot be completed if one turned in the modified FEV to Owyn Lyons before departing the Citadel.

Inserting the modified FEV lowers Karma by 1000 and has a long-term game impact if one has Broken Steel installed. The Aqua Pura thus created by purifying the water is now infected by the virus and as the player character is not a pure-strain human as Eden believed, it will cause a negative effect on their SPECIAL stats and kill the Lone Wanderer if four or more are consumed in quick succession. A warning will come up that reads "Continued consumption of FEV-laced water will be fatal" to remind one of this fact.

Decision 2: Have your radiation-resistant companion do it
Without Broken Steel installed, the Lone Wanderer's companions will refuse to do the job. Naturally, of the seven, four would die just as easily as the Lone Wanderer and they are not willing to do it. Even Fawkes, Sergeant RL-3, and Charon who are highly resistant or immune to radiation will simply decline. With Broken Steel, however, the latter three will now agree to do the job, as they can do it safely.

Companion Responses
Fawkes, one of the companions the player character may take with them, has great radiation resistance (or possibly immunity) as a result of being a super mutant. However, like any other companion character, his dialogue option has him refuse to enter the chamber, mysteriously claiming it is the player character's "destiny." Fawkes may nonetheless follow the player character into the chamber if his following distance is set to "close."
 * Fawkes

If the Broken Steel add-on is installed before beginning Take it Back!, Fawkes will agree to enter the chamber, stating this.

Fawkes will be briefly staggered when the purifier activates but does not collapse as the player or Sarah Lyons would. He will instead walk around the chamber and kick the purifier panel as the screen fades to white. The end will show him as "A True Hero" instead of Lyons.

There is no option to have Dogmeat activate Project Purity. Instead, a new dialogue option opens up, wherein the Lone Wanderer can say some final words to his or her canine companion, stating: "I think it's time for us to say goodbye, old buddy. Take care of yourself, okay?" Dogmeat whines in response.
 * Dogmeat

Even if one took Sergeant RL-3 (a Mister Gutsy combat robot, which is immune to radiation) into the rotunda and command it to go in to turn on the purifier he declines and says:
 * Sergeant RL-3

There is no Robotics Expert dialogue option in the conversation.

Like Fawkes and Charon, if Broken Steel is installed before starting Take it Back!, RL-3 can be ordered to go into the control chamber and activate the purifier. He will state that his "superior design and programming" will be able to withstand the hostile environment, followed by an exclamation that "this will mean a battlefield commendation for sure."

After starting the purifier, he cringes but is otherwise unharmed. The ending will show him as "A True Hero" instead of Lyons.

Charon will not activate the purifier. The dialogue is as follows:
 * Charon

Just like Fawkes, if Broken Steel has been installed before this quest, Charon can be told to enter the control chamber and turn it on. The player character will remind Charon that he must obey whoever holds his contract, then order him to enter the control chamber, to which Charon grudgingly agrees.

Unlike with Fawkes or RL-3, no mention is made of the fact that Charon, being a ghoul, should be unaffected by the radiation in the chamber. If Charon is used to start the purifier, he will replace Sarah Lyons as "A True Hero" in the ending movie.

Butch will refuse out of fear of dying and of becoming a ghoul, stating:
 * Butch

Star Paladin Cross refuses, stating:
 * Star Paladin Cross

Clover refuses as well:
 * Clover

Jericho also refuses, stating simply:
 * Jericho

Decision 3: Do nothing.
If one chooses to, they may simply not go into the purifier. This results in Project Purity quickly exploding, along with any chance of pure water for the entire wasteland or to introduce the modified FEV into the water supply. An ending sequence will still be played, and it will count as an ending (completing the quest and unlocking the "Take it Back!" achievement/trophy). The last thing the player character will see is the destruction of the purifier. Just like all other endings, this does not result in free-play. Even if Broken Steel is installed, this option ends the game. With no purifier the events of Broken Steel could not happen.

Conclusion
In all events, completing this quest will present one of the Fallout 3 endings. However, depending on one's choices and the game's installation, the game could either continue into the events of Broken Steel, or simply end.

Game over
The credits will roll and return to the title screen, if:
 * The Broken Steel add-on is not installed, there's no continuation after this mission regardless of the decision made (sending Sarah or not, or even letting the purifier explode).
 * The Broken Steel add-on is installed, however:
 * The purifier is destroyed (by not entering the correct code or allowing Sarah to do so), or
 * A companion manages to enter the chamber along with the player character (running around to the furthest side from where you entered, having your companion glitch into the chamber).

Broken Steel
However, if Broken Steel has been installed and the player character activates the purifier instead of allowing it to explode, the player character will wake up two weeks later at the Citadel.

As the Lone Wanderer wakes up, they encounter Elder Lyons, who explains that both they and Sarah Lyons were both knocked unconscious due to an energy spike in the purifier and were found and brought back to the Citadel. Sarah has either died, if she activated the purifier, or has not yet recovered from her coma if she didn't. Elder Lyons also explains the consequences of their actions, including the destruction of Raven Rock or the insertion of the modified FEV into the purifier. The first Broken Steel quest, Death From Above, starts here.

Ending
The ending varies depending on how the player plays the game, and some of the largest differences are seen depending on what the player has done during Take it Back! See Fallout 3 endings for more info.

Bugs

 * Liberty Prime may not appear at all during the battle, simply disappearing from the bailey of the Citadel. This can make the battle against the Enclave extremely difficult as artillery will still pound the bridge.
 * If a player causes the opening cut scene to start but leaves, (i.e. by leaving once their conversation is started, but before the player is immobilized) there is a chance that when the player returns to allow the cutscene to play out, none of the controls will work and the game will act as if Elder Lyons and Sarah are speaking, therefore barring the player from starting Take It Back! or beginning the Broken Steel expansion.
 * When Liberty Prime is crossing the Potomac bridge, depending on the bombardment, it is possible for him to get stuck on the bridge after being hit by a blast. Liberty Prime may also get stuck by the Enclave's drop ships on the bridge. Firing a few mini nukes from the Fat Man at the drop ships will clear the road so Liberty Prime can resume its path. Fast traveling to another location and back may also dislodge Liberty Prime, allowing him to continue. Teleporting Liberty Prime to the player can also do the trick.
 * At one point, all members of the Lyons' Pride kept shooting at an Enclave corpse (as did Charon) and the player was unable to interact with the body. Charon will simply stop and follow the player once again if the player walks too far away, but there is no known way to get the Lyons' Pride to continue.
 * After leaving the Citadel, Liberty Prime may just stop moving altogether. If this happens, reload an earlier save and he should start to move. If you can't, just go in contact with the energy barrier and use the console command . This will trigger the robot's ability and the quest will continue normally.
 * It's possible for the game to randomly freeze during initial invasion. It could be caused by moving too far away from the Pride.
 * It is possible for Sentinel Lyons to not follow you into the Rotunda, leaving you with no way to enter the purifier and no way to leave the Rotunda. If this still isn't fixed after restarting Fallout 3, use the console command . This may solve the problem. It can also be solved by quick-saving on the PC in the Rotunda and then quick-loading.
 * Liberty Prime may stand in place and not commence his attack. It is possible the Lyons' Pride cannot be assembled if Paladin Vargas was killed earlier in the game. If so, his body will be in front of the Citadel entrance; you will need to carry him over to Prime's feet to get him to initiate his attack. Or if you can't find the body then use the console Command player.placeatme 0001d44e. Another alternative is to use Stealth Boys or Chinese stealth armor and attack Liberty Prime. He won't be able to find the player, but will follow the shots, and can be led to the first barrier. From there he should continue on as normal.
 * If you download the Broken Steel expansion, Sarah Lyons may sometimes ask to make sure the room is clear after she talks to the doctor, despite no enemies being in the room. This will make it impossible for the player to activate Project Purity. This glitch can be fixed if one downloads the V1.5 update/patch. This glitch can also be fixed by clearing the Fallout 3 cache (separate to the system cache), when you click "play game" keep hold of the left bumper, right bumper and X until the "Press Start" text appears, after loading the game this should be fixed. Another way is by making a save when Sarah closes the chamber door (possible if you haven't yet installed Broken Steel; if you have then delete it from the hard drive). Now after you have saved the game you install Broken Steel.
 * The bug may also be fixed if you change the difficulty, then reload the confrontation with Autumn.
 * If the player continuously walks into Lyons it is possible to trap her inside the Purifier. If you push her in far enough and shoot her until she turns aggressive and then push the airlock button she will run out as it's closing and run down the stairs. The game then freezes for a few seconds and the screen turns white with the radiation bar still showing.
 * The multiple blasts and fireworks may cause some screen & textures problems, displaying strange effects in the sky and on the ground during the battle, causing the game to eventually freeze. This could force you to restart your console. If experiencing this kind of problem, save the game when bugs are starting and then reloading it right after may resolve it.
 * If you start the Head of State quest, you may see the brahmin from the Temple of Union. If you kill it, then either continue or go away from fast travel, Liberty Prime may find Hannibal, Caleb, and the rest of them hostile and kill them. You will get the message saying "Hannibal and Caleb have died" and fail the quest.
 * Sarah Lyons may not be killed, and a glitch may occur where you knock her out, and drag her into the Purifier. If you close the door, she will wake up non-hostile, and you can talk to her and tell her to turn it on, or you will do it.
 * If you tell your companion to wait in the rotunda while the purifier is activated, they will not be there on return trips to the rotunda (due to the area being instanced), nor will they have returned to their usual meeting place (where they go after they are fired). PC players may reacquire companions by using the console command player.moveto , instructing your companion to follow you, then exiting the monument. On any platform, players can leave the Capital Wasteland via The Pitt or Point Lookout, which will result in your companions being fired and returning to their usual spot, where they can be re-hired on return to the Capital Wasteland. If you have Mothership Zeta DLC, it may also be possible to go to Mothership Zeta and have the follower on the ground upon your return but there is no sure way of knowing. Lastly, if you just wander around the Capital Wasteland long enough, your followers will eventually leave your employ and return to their default locations.
 * The entire fight can be avoided by simply going to the Jefferson Memorial before you start the fight, and doing some trick jumping to get inside the blue fences. Once inside continue inside the Jefferson Memorial and to the Rotunda where you will see Colonel Autumn pacing the room where Dad was killed. Wait until Autumn enters inside the room where you originally will end up putting the G.E.C.K. and go to the switch and close him in the room. In which the other door will open and will start the confrontation. The only problem with this method, is that if Broken Steel is installed, the Enclave energy barriers will still be up and operational even though we could assume Liberty Prime took them down.
 * Upon exiting the Citadel through the main entrance, Liberty Prime will remain behind the small metal bridge next to the entrance. The Lyons' Pride (excluding Sarah) will eventually spawn and proceed as normal with the robot, until on the main bridge. After a series of Prime's missile attacks and the destruction of the vertibirds, the screen (but not any functions) will black out whenever facing the same direction as Prime, to the sides and in the opposite direction are normal and V.A.T.S can still be entered. However this will severely hinder the player's ability to contribute to the battle. It appears to wear off when in front of Prime at the Jefferson Memorial. This glitch does not affect the story ending or Broken Steel.
 * A bug concerning Fawkes has been noted if you have the DLC, Broken Steel installed. It is possible that just before you enter the rotunda room and if you have Fawkes as a companion, he may disappear after you have completed the quest and will never return to the Museum of History. Alternatively, he may be found 'stuck' outside the Jefferson Memorial in an inaccessible area and cannot be spoken to or reached in any way as the railings prevent you from doing so. This has been noted to happen regardless of whether Fawkes enters the rotunda room with you or if you fire him and ask him to return to the Museum of History, just before you enter the rotunda. This bug may be resolved by either loading an earlier save prior to entering the rotunda or if you have any of the other DLC installed. Entering a DLC area should force him to return to the Museum of History. A more successful known way of preventing this bug is to load a save before undergoing 'Take It Back!', by asking Fawkes and any other companion to return to their waiting spot before leaving the Citadel with Sarah. This way none of your companions will interfere with the quest, therefore preventing the bug and any of the other bugs above. It should also be noted that other companions such as Dogmeat have also been known to disappear after completion of this quest and do not return to their usual waiting spot. However, if you simply wait or sleep for several days and then return to their usual waiting spot you should find that your companion has returned despite not receiving the message indicating that they have done so.
 * After activating the purifier the screen will turn white. If you decide to pause the game at that moment, navigating through the menu will not generate any sound as it normally does.
 * It has been noted that occasionally, if you run past Prime towards one of the barriers, at some point Prime will disappear completely.
 * Around the far side of the catwalk the player may encounter two friendly Enclave troops standing in place. They can be engaged in conversation, but the only speech option is "See you later", which ends the conversation.
 * If the player is able to see Autumn by carefully edging along the wall to avoid conversation, and kills him with a single hit, the other two Enclave troops in the room will remain friendly. The option to speak to them appears, but they say nothing. The final part of the quest to activate the purifier will not trigger however, and the player must kill them to proceed.
 * When you start the purifier it may go through the cutscene, but then go black and back to normal after which you'll still be in the control room, unable to move. Loading an early save should fix this.
 * It is possible for Fawkes to spawn randomly in front of the Citadel, towards the bridge crossing the Potomac. Should this happen, Fawkes will be killed when Liberty Prime launches his first attack, as can be found when finding bits and pieces of him.
 * The end cinematic may cause a crash.