The Battle of Bunker Hill is an Institute main quest in Fallout 4.

Quick walkthrough

Institute Main Quest: The Battle of Bunker Hill
Talk to Father.
Inform the Brotherhood.Inform The Railroad.
Meet the courser outside Bunker Hill.
Kill the courser and leave. (Railroad)
Find the escaped synths.
Kill the synths. (Brotherhood)
Issue synth reset codes. (Institute)
Speak to Father
Reward: 500 XP
500 caps
Leads to: Mankind - Redefined

Detailed walkthrough

Father orders the Sole Survivor to go to Bunker Hill to reclaim some escaped synths, held there under the protection of the Railroad. The player character will have backup from a courser designated X4-18. Exit the Institute and proceed to Bunker Hill.

Optional: If Shadow of Steel has been completed, the player character can warn Elder Maxson about the Institute's plans, and he will ask the player character to kill the synths when the opportunity arises. If Tradecraft has been completed, it is also possible to warn Desdemona that the Institute is on its way, which will allow the Railroad to anticipate their arrival and lay an ambush. Both groups can be warned or ignored, however despite Desdemona and Maxson saying they would have had no idea of the Institute's intentions if the player character had not informed them, all three factions will be present at the hill battling, regardless of the player character's actions.

At Bunker Hill, the battle begins only after the player character meets with X4-18. He explains the situation to the player character and calls in backup, at which point the player character can pass a hard persuasion check to get more synth relay grenades. (Note: If both the Brotherhood and Railroad were informed, this second piece of dialogue will be unavailable and the courser advances towards Bunker Hill after the first dialogue.)

The main doorway into the settlement is locked, requiring the Sole Survivor to walk around to the east (right) side of the settlement where an opened door can be found. Alternatively, it is possible to climb the trailers to the right of the locked gate and jump over the fence. The inhabitants of Bunker Hill will cower during this firefight, so it is likely that most if not all of them will remain alive (due to varying "essential" statuses), despite the free-for-all taking place around them.

Once inside Bunker Hill, there should be a small doorway into a utility basement behind one of the counters. After following the catwalks to a room far in the back, the player character finds the runaway synths Z3-22, B2-57, Y9-15 and F6-33. Here the player character has three options:

  1. Option 1: Escort the Courser to the escaped synths and let him take them back to the Institute. To complete it, simply proceed through the fighting to where the synths are hiding, activate their 回收代碼 by speaking to them individually and allow X4-18 to take them back. This does not turn the Railroad or the Brotherhood into enemies if they are not hostile and does not eliminate the player character's good standing with them.
  2. Option 2: Kill the Courser and free the synths. In dialogue with the synths, tell them that they are free to go, which immediately turns the Courser hostile and brings up the objective "kill the Courser." If not allied with the Railroad, killing X4-18 will immediately turn the Railroad members and turrets friendly (which will be revoked if one opens fire on them. If X4-18 is killed above ground, Railroad members underground may be hostile).
  3. Option 3: Kill the escaped synths. Killing them makes the Courser hostile, but killing him immediately switches the Railroad members to friendly, whether the synths are killed before or after.
  • Additionally, the player character can accept an offering of 60 caps from one of the synths. This does not affect the available choice, so it is possible to accept their money and send them back to the Institute anyway.

Regardless of choice, a new objective will be added to report to Father on the roof of the ruins of C.I.T.. The roof is accessible from the easternmost staircase inside the main entrance of the ruins. After a short discussion about how the Commonwealth has declined, Father speaks of Bunker Hill:

  1. If Option 1 was taken, he applauds the player character's success and rewards them with 500 caps.
  2. If Option 2 or 3 were taken, he demands to know what happened. Wrong dialogue choices here, such as admitting it was the player character's fault, can lead to being banished from the Institute. Stating that it doesn't matter, or that they were ambushed, makes Father upset with the outcome but ultimately preserves the player character's good standing with the Institute.

The quest concludes, and if the player character's good standing with the Institute is preserved, Mankind - Redefined begins.

Quest stages

10 Speak with FatherI need to find out what Shaun wants.
20 (Optional) Inform the Brotherhood of Steel
30 (Optional) Inform the Railroad
40 Meet up with the courser at Bunker HillI've been tasked with helping to recover synths that have escaped from the Institute and fled to Bunker Hill. There's a courser waiting for me just outside the settlement.
50 Find the escaped synthsWorking with a Courser from the Institute, I need to find the escaped synths hiding in Bunker Hill.
60 Decide the fate of the escaped synthsWe've found the escaped synths. Now to issue their recall codes so they can be returned to the Institute.
We've found the escaped synths. Now to either issue their recall codes, or destroy them.
We've found the escaped synths. Now to either issue their recall codes or turn on the Institute.
We've found the escaped synths. Now to decide their fate.
91 Kill the CourserI told the synths they're free to go; I have no choice to but to destroy the Institute Courser now.
100 Speak with Father in the ruins of CITI need to return to the Institute and tell Shaun what happened in Bunker Hill.
200Quest finishedQuest complete
1500Quest failedQuest failed


  • Until speaking to X4-18, Bunker Hill remains in its default, non-combat state. This allows the player character to pursue other quests, such as Traffic Jam and Prep School, and they will become available again once this quest is turned in. Once X4-18 is spoken to, however, Bunker Hill's combat state will be loaded, with Railroad heavies instantly in position, the front gate locked ("Requires key") and Vertibirds flying in from the background.
  • When meeting up with X4-18, Vertibirds will be heard in the background. Hurrying through the dialogue will allow the Sole Survivor to persuade him through a hard Charisma check for three synth relay grenades. Taking too long will skip that part of the dialogue and instead receive the recall codes.
  • If Tradecraft has not been completed, the optional objective to inform the Railroad will not be available. Similarly, if Shadow of Steel has not been completed, the option to inform the Brotherhood of Steel will not become available. If these quests are completed once "The Battle of Bunker Hill" has been added to the journal, the optional objectives to inform the factions will not be added.
  • If the player character is an inducted member of the Railroad and the Brotherhood of Steel (i.e. completing Tradecraft for the Railroad, Call to Arms for the BoS) and in good standing, the fighters of all three factions will be marked as friendly, ignoring the Sole Survivor. This not only mitigates most of the danger this mission might pose, it also allows for the acquisition of ludicrous amounts of valuable loot.
  • If Underground Undercover and From Within have not been added to the journal (possible by entering the Institute with the help of the Minutemen), the player character must go through those dialogues before Desdemona and Maxson can be warned.
  • If the player character "chooses a side" by firing on the other factions' NPCs, the chosen side will slowly gain the upper hand until they've successfully dispatched the rest of the factions' reinforcements. If the player character has remained "neutral," because X4-18 is marked as "protected" he cannot be killed unless attacked by the player character, so he will eventually kill everyone else. If the player character fires on one side, hostile members of that faction will have to be fought on the way back out. The synth striders brought to the battle do not turn hostile if the Courser is killed.
    • Informing any other factions ahead of time is not required to employ options 2 or 3 (aside from possibly bugging the "Deal with the synths" objective as displayed in the journal); one can kill the Courser or the synths as one sees fit. It is also possible to accept a bribe of 60 caps from the synths, no matter what option one chooses in dialogue.
  • Upon completing this quest, the player character can unlock Bunker Hill as a settlement by speaking to Kessler. She cites the player character's "powerful friends" and allows them to have the run of the place.
    • Completing this quest is not the only way to unlock Bunker Hill as a settlement. Should the Sole Survivor get Banished from the Institute before completing this quest, one could complete Prep School and then talk to Kessler afterwards.
  • Companions have unique thoughts after the battle.
  • Danse and Deacon have no reactions to warning either the Brotherhood or the Railroad. Similarly, their affinity does not change in response to killing the synths, freeing them, accepting a bribe or sending them back to the Institute.

Behind the scenes

The title of this quest is a reference to the historical Battle of Bunker Hill, an important conflict of the American Revolutionary War occurring near Bunker Hill in 1775. Contrary to popular belief, the bulk of the fighting during the Battle of Bunker Hill took place at the site of the American redoubt on Breed's Hill, not Bunker Hill. The Bunker Hill Monument was erected at the site of the battle, on the peak of Breed's Hill. Thus, both historically and in-game, the Battle of Bunker Hill takes place on Breed's Hill, not Bunker Hill.


  • Has platform::PCPC Has platform::Playstation 4Playstation 4 Has platform::Xbox OneXbox One If you respond negatively to Father at the end of this quest and get Banished from the Institute, the named settlers in Bunker Hill may be stuck cowering.[已验证]
    • It is possible to fix this with the console command stopquest ef21c and then fast-traveling or sleeping.
    • Has platform::Xbox OneXbox One NPC's may become permanently stuck cowering as the Battle for Bunker Hill will never stop.
  • Has platform::PCPC Has platform::Playstation 4Playstation 4 Has platform::Xbox OneXbox One If any caravan (e.g. Doc Weathers) and their guards are in the area, they are hostile to all faction members.[已验证]
  • Has platform::PCPC Has platform::Xbox OneXbox One After informing the Brotherhood of Steel or the Railroad, killing the courser before meeting the synths can break the quest, causing the synths to think they're being freed by the Railroad (even if you've destroyed the Railroad). Killing them when you do meet them and you've already killed the courser will result in a 'kill the courser' objective (which is impossible seeing as he's already dead), and 'Speak with Father' objective (note: not to be confused with 'speak with Father in the C.I.T. ruins'), and a quest marker inside the Institute, but Father is nowhere to be found.[已验证]
    • A possible workaround is by reloading a prior save.
  • Has platform::Playstation 4Playstation 4 Has platform::Xbox OneXbox One None of the faction NPCs will be hostile to the player character, even upon attacking them. However, if one attacks too many Railroad Heavy agents in a short period of time, the Railroad will become hostile and Deacon will attack the Sole Survivor if brought along.[已验证]
    • This can be exploited for easy EXP as there are no repercussions.[已验证]
  • Has platform::Xbox OneXbox One The front gate will be locked once the battle starts, and will remain locked for the duration of the game unless the player clears out all the turrets inside the hideout, where the four synths are kept. All turrets must be destroyed while this quest is still active since they become invincible once the quest is completed. This bug and its workaround applies no matter which faction the player supports. An effective workaround to this, in case the turrets are now invincible, is to craft a fast travel mat, and then set it to wherever you'd like your fast travel target to be.[已验证]
  • Has platform::PCPC The game may freeze when going to talk to Father at the C.I.T. ruins at the end of the quest. Patched as of v1.2.[已验证]
  • Has platform::PCPC One or more of the factions will become hostile toward the inhabitants of Bunker Hill if the inhabitants get hit in the crossfire, which will make them instantly hostile towards the group(s) that accidentally fired upon them, prompting such confusing scenes as a Railroad NPC repeatedly firing his weapon at an unarmed and cowering child.[已验证]
  • Has platform::PCPC If any NPC kills the parent of a child NPC, where the child is in the same faction as the parent (not to be confused with join-able factions), this would normally result in instant hostility between the child and the NPC responsible for the attack. Since children in Bethesda games are scripted to flee and are hard-coded as essential and thus completely invulnerable, a bug occurs when the game AI are responsible for the attack or allied with attacker, and NPC/turrets will relentlessly fire upon the child and can even crash the game if too many turrets are firing continuously at the same time. Same situation occurs if you are in a settlement and attack the parent yourself, even if by accident. Once the parent dies, the game-controlled turret will relentlessly fire upon the child NPC indefinitely as the child belongs to the same faction as the parent and is now considered hostile. Appears to be a blatant oversight in the programming where the children are not fully ignored.[已验证]
  • Has platform::PCPC Has platform::Playstation 4Playstation 4 Has platform::Xbox OneXbox One After completing the mission, upon returning to the utility basement, the remaining living allied faction NPCs will die upon entry, made known by an audible death-throe cue (also visible with General Subtitles on). This allows the player for a chance at looting powerful equipment such as the Railroad armored coat, Gauss rifles, and ammunition.[已验证]
  • Has platform::PCPC A Brotherhood Lancer Initiate may stand near on the path between the Obelisk entrance and the Market. He cannot be interacted with, and he cannot die, but he will continually draw fire from any synths or Railroad heavies that are left.[已验证]
  • Has platform::Playstation 4Playstation 4 If you complete the quest, and then fast travel back later, ALL non-Bunker Hill NPCs will die upon arrival (Railroad Heavies, Brotherhood of Steel Knights, Synth Striders, etc.), causing your game to lag behind or crash.[已验证]
  • Has platform::Playstation 4Playstation 4 Has platform::Xbox OneXbox One It is possible that no one underground can be targeted in VATS, damaged by the player, or damaged by each other. The battle appears to continue indefinitely and the quest cannot be completed.[已验证]
    • To prevent this, turn against the Institute, once you have taken care of the synths the Courser will turn against you. The quest will be updated to tell you to kill the Courser.