Defiance Has Fallen

Defiance Has Fallen is a main quest in Fallout 76. It is part of the Brotherhood of Steel quest line.

Background
Years ago, the Brotherhood in Appalachia sent out a cryptic message saying that Defiance has fallen. Nobody outside the Brotherhood knew what that meant - it is up to Vault Dwellers to figure out the mystery.

Quick walkthrough

 * After completing Coming to Fruition, the quest can be started by reading the "Fort Defiance" entry on Abbie's terminal in Abbie's bunker.
 * It can also be started before reaching this point and finishing the Free States quests.
 * Travel to Camp Venture and read the Letter to Tommy. The letter is located inside the command center and requires the command center password to access.
 * The command center password is in a locked secure storage room in the basement of a building outside the main walls. The key to this room is in a locker in the barracks.
 * Travel to Fort Defiance.
 * Power up the building by finding a circuit breaker on the third floor. Watch out for a glowing wendigo or feral ghoul guarding it as the boss enemy.
 * After powering up the building, return to the mag-locked door near the entrance and press the red button to open it.
 * Read the Final stand note which is pinned to the board near the door to complete the quest.

Abbie's bunker
Travel to Abbie's bunker and look for her terminal which is located in her bedroom. Once there, read the entry titled "Fort Defiance."

Camp Venture
Next, travel to Camp Venture which is located directly east from the National Isolated Radio Array. Be prepared to clear the area of creatures. Once the area has been cleared, find the secure storage key in the barracks. It will be locked in a locker that can be picked. After the key is obtained, find the V.E.S.T. building on the lower side of the camp. in the basement, there is an orange door. Unlock it with the key and look inside for a note on a table called Command center password. Next, find the command center building, which is guarded by a terminal. Once inside, look for the letter to Tommy which is located on a table.

Fort Defiance
Fort Defiance is located on the edge of the Cranberry Bog and Savage Divide inside the Allegheny Asylum building. Be ready to fight more Scorched outside, and strong feral ghouls inside, possibly including a wendigo.