Talk to Father and he will tell you about the Railroad and the Synths they are helping to escape. He wants you to travel to Bunker Hill where they are and bring them back.
Note: If you have also been working with the Railroad or the Brotherhood of Steel you can go inform them of the upcoming attack on Bunker Hill, but for the sake of simplicity, it will be assumed you're staying loyal to the Institute.
Here meet up with your Courser contact (not X6-88) and he will brief you on your situation. You can talk to him and attempt to pass a hard speech check for extra grenades as well. With that done, the Courser will give you the "Recall Codes" for the Synths (to shut them down easily). Time for the battle itself.
Note: If you are allies of each of the factions here (Railroad, Brotherhood, Institute) none of them will attack you. This makes this mission very easy as you can imagine, but you can also use this situation to your advantage by letting the factions kill themselves here and then freely looting their corpses. Power Armor and all.
This battle is pure chaos. There is no other way to describe it. Railroad Fighters, Institute Synths and Brotherhood of Steel soldiers will all be fighting here and trying to kill each other. The Railroad has the town itself (and the defenses) but objectively the Brotherhood is definitely the most powerful force here. You will see them come in with Power Armor, Gatling Lasers, Miniguns and even Vertibirds, which do provide reinforcements and fire support. The Institute for its part provides distraction by warping in Synths, usually at the corners of the streets.
You'll start out on the south side of Bunker Hill. The usual gate here is barred, so you will need to head left, wrapping around the streets to the east side. Bah... Go ahead and start down the streets, avoiding or fighting the enemies as the situation warrants. Wrap your way to the east entrance and head in, then make your way to the obelisk. From there head north to the market to find a trapdoor leading down to a Utility Basement behind a counter, which is your destination.
You are now underneath Bunker Hill, where the fight continues. Head down the linear path until the room opens up and you can see the battle waging. Fight who you must and head to the north-west corner and up the small steps and enter the room here (Institute Synths are likely coming out of here). Hang a left and follow this path up past the entrenched Railroad forces, which may just be an annoying, loud, light show if you're not hostile with anybody, but be wary, as there are some levelled turrets you have to deal with no matter who you're allied with. At the end of your path you'll find four escaped Synths, each of which you'll need to talk to and use the recall code the Courser gave you at the beginning of the mission. Go ahead and turn each one of them off (don't bother with the money the one offers), after which the Courser will thank you and warp them back.
Note: After the fighting, you can talk to the Mayor of Bunker Hill, Kessler, who will tell you that "You have powerful friends" and lets you use the workshop here, which means that Bunker Hill is unlocked as one of your settlements!
After you are done, you will be told to go meet Father at the C.I.T. Ruins. He is actually on top of the roof, which means you will need to enter and hang a right, going past the first set of stairs and head all the way back, finding a second set of stairs past the bathrooms. Take this set of stairs up to the roof and talk to Father, who will babble on a bit about the Commonwealth and about your escape from Vault 111 before asking you to return to the Institute and attend a board meeting with him. This officially finishes "The Battle of Bunker Hill" quest and starts the next quest, "Mankind - Redefined" .
|For securing your objectives at the Battle of Bunker Hill||590 XP 500 Caps|
Mankind - Redefined
This is a simple enough "quest", if you can even call it that. Head back to the Institute and follow the objective marker to the Board Room. Take a seat once you get there and listen to the meeting. You will have several opportunities at dialogue as the meeting proceeds, but you will learn what exactly "Phase 3" is. You will also learn of "Father's" condition. This turns into a talk of who will lead the Institute, where, well, they make the right choice. For now, just ask what that means and you will be given a basic run-down. You will also be asked to assist with Phase 3 and the quest will officially come to a close. After waiting a few moments you will automatically get the next quest in the chain, "Mass Fusion" .
|For being named Father's successor||472 XP|
Complete "Mankind Redefined".