Shadow of Steel

Shadow of Steel is a Brotherhood of Steel main quest in Fallout 4.

Detailed walkthrough
After observing a huge Brotherhood of Steel airship pass overhead, the player character's Pip-Boy radio receives a transmission. Listen to it for further instructions before heading to the Cambridge Police Station and following Paladin Danse to the roof.

At the Brotherhood of Steel's flagship, the Prydwen, disembark onto the flight deck and meet Lancer Captain Kells.

One is ordered to attend an address being given by Elder Maxson. Speak to Maxson afterwards. Regardless of the earlier rank in the Brotherhood, Maxson now bestows the title of Knight on the Sole Survivor and a new suit of power armor which can be found in Bay 3 of the main deck.

Nick Valentine dialogue

 * Diplomacy : "It sure as hell ain't gonna be taken as a gesture of good faith from the other forces in the Commonwealth."
 * Provoking War : "No one brings that much firepower without plans to use it." [Valentine liked that.]
 * Who is Maxson? : Valentine will call Maxson a lunatic.
 * Quick War : Valentine will ask "Yeah, for who?" [Valentine disliked that.]

Hancock dialogue

 * Diplomacy : "Ain't no one in the Commonwealth wondering about your intentions now."
 * Provoking War : "Folks don't usually appreciate having a floating fortress blocking their view."
 * Quick War : "Sure know how to make an entrance, I'll give you that."

Bugs

 * If you did not complete Call to Arms before the Prydwen appears after Reunions, this will trigger a glitch where Brotherhood Vertibird patrol teams will not spawn correctly.
 * If an NPC clips through Paladin Danse while you are reporting to him, the dialogue options may disappear and cannot be pulled back up. When you try to talk to him again, he will only say «I'll be in the mess hall if you need me. Good luck with Maxson» making the quest impossible to complete, and will leave you unable to talk to most of the other Brotherhood of Steel members. One possible workaround without involving console command would be dismissing any companion you have with you before talking to paladin Danse. This bug seems to be triggered by the fact that Paladin Danse is supposed to become your new companion, while the current one cannot be correctly dismissed. Doing it in advance should avoid the issue.
 * If you do not leave via the elevator, Shadow of Steel quest won't trigger. You need to exit through the elevator door.
 * This quest will show up before Reveille in the completed section of your quest log, even if you received it afterwords.
 * The game sometimes will bog down and crash while flying from Cambridge Police station to the Prydwen. If this happens, you probably have a corrupt save, delete all saves and restart.
 * The vertibird may not take off of the Cambridge Police Station roof, and Danse may talk as if the vertibird is in the air. There are no known fixes for this issue.
 * If you hear a sound like two objects are collision bugged, and the vertibird do weird movements, your companion is probably bugged into the vertibird, reload the save just before get in the vertibird and then say him to go in a settlement.
 * If you complete Far Harbor missions prior to starting this quest then you will be unable to complete 'Speak to Lancer Captain Kells' stage of the quest as the moment you approach the miscellaneous 'inform the BoS about the synth refuge' dialogue will automatically be triggered (trying to end that dialogue will just cause it to retrigger). Leaving the location and returning should fix it.

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