Semper Invicta Main Story, Brotherhood of Steel Quest
This quest will be triggered or can be aquired when you complete Call to Arms quest.
Related points of interest
Stages of "Semper Invicta" quest
1. Return to Cambridge Police Station
After agreeing to join the Brotherhood of Steel, Paladin Danse has asked me to return to the Cambridge Police Station for my next assignment.
I've refused to join the Brotherhood of Steel, but if I wish to reconsider, Paladin Danse has told me to return to the Cambridge Police Station.
2. Speak with Paladin Danse
At the end of the conversation you will receive new quest - Shadow of Steel.
3. Support the Brotherhood Recon Team
I've accepted Paladin Danse's offer to join the Brotherhood of Steel. Now that I'm a member of the team, I should assist Knight Rhys and Scribe Haylen with their current assignments.
To complete this stage you have to finish two quests, one for Scribe Haylen and one for Knight Rhys:
4. Quest completed
I've completed my initial assignments for Knight Rhys and Scribe Haylen.