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Help finalize the Weather Machine repairs

Oldest Trick in the Book is a main quest in Fallout 76, introduced in the Skyline Valley update.

Quick walkthrough[]

Detailed walkthrough[]

Immediately after completing Seeking Shelter, Audrey walks up to you to comment on the repairs. Hugo suddenly runs in and interrupts the conversation to say that Cassidy has been kidnapped by cultists. Based on the knowledge from Seeking Shelter that the leader of the cultists is called Alex, Audrey concludes that the leader must be her former love interest Alex Guerra. When Hugo lets it slip that he tried to have Alex assassinated, Audrey becomes dismayed and leaves. Hugo suspects that the cultists are holed up at Old Crimora Mines, and suggest that you infiltrate the cult and kill Alex. If you say that you do not want to kill Alex, he changes his mind and gives you Audrey's book, to be given to Alex as a peace offer.

Travel to Old Crimora Mines. You must wear cultist clothes to ensure that cultists do not recognize you as an agent of Vault 63; you can find cultist's garments in the small shack to the right of the mine entrance. Enter the mines and keep walking until you reach Disciple Blair. Take a right until you reach a small altar, and pick up the cultist prison key from the duffle bag against the cave wall to the left of the altar. Turn around, take a right, head deeper into the mine, and take the stairs. If you are violently inclined, kill Elder Pepper and proceed into the tunnel. Otherwise, cross the bridge and walk past Adept Scarlet into Alex's room, read the password sheet to learn the password, return to Pepper, and tell him the password.

Keep walking until you reach a downward slope. Halfway down the slope, open the prisoner door using the key you picked up earlier, and enter the room to find Cassidy. Continue down the slope, and head deeper into the mines until you reach a large ritual chamber with a bonfire surrounded by cultists, and Alex to the left. Walk up to Alex, and either kill her outright or talk to her.

If you choose to talk with the cultists and Alex, you will quickly find that many secretly do not worship mothmen, and are only interested in taking revenge on Hugo. Alex corroborates this, and claims that Hugo has displaced the Shenandoah population to build Vault 63, promising shelter in the vault but walking back on his promise before the Great War; and that Hugo tried to have Alex assassinated because she was distracting Audrey from working for her father, but failed because the Great War happened exactly when the would-be assassin tried to kill Alex.

Upon handing Audrey's book to Alex, she will open it, activating a poison trap and killing her almost immediately. The cultists will turn hostile, and must be killed. The quest does not proceed until all cultists have been killed, even those that are not hostile. Fight your way out of the cave and return to Vault 63.

Talk with Hugo to report on your progress. Audrey, apparently having overheard your conversation, walks in and directs a tirade toward Hugo, holding you both accountable for Alex's death, before leaving again. Hugo stoically gives you your reward, completing the quest. Once both this quest and James Oberlin's Double-Crossed Wires have been completed, Gathering Clouds will begin.

Quest stages[]

Quest stages
StageStatusDescriptionLog Entry
? Speak to AudreyI've installed the replacement part as Audrey requested. I should let her know it's done and see if there is anything else she needs my help with.
? Go to the <Alias=Loc_StormCultistTunnels>Cassidy has been kidnapped. Hugo wants me to infiltrate the cultist's base at the Old Crimora Mines, deal with Alex and the other cultists, and locate Cassidy so his men can extract her.
? Find and equip a disguiseI've arrived outside the Old Crimora Mines. I could rush the gate and clear them all out, but Hugo wants me to blend in fearing they might harm Cassidy if I'm spotted. Maybe I can find a disguise around those cultists standing guard at the entrance.
? ZZZ Kill the cultists standing guardI found some Cultist's Garments I can use as a disguise. I should put it on so I can search for Cassidy unnoticed. I probably shouldn't take it off while I'm in there or I'll blow my cover.
? Investigate <Alias=Loc_StormCultistTunnels>I should have a look around to see if I can find any clues to where they are keeping Cassidy. Maybe I could try talking to some of the cultists while I'm in disguise, they might tell me something useful.
? Investigate the upper area of the minesI found a note that mentions an upper area of the mines and some cultist named Elder Pepper, who appears to be gating off Alex. I should have a look up there, see what I can find.
? Search for Pepper's passwordThis cultist Pepper blocked my way because I didn't know the password. If I do run past him I run the risk of blowing my disguise. Maybe one of the other cultists knows something about it ?
? Return to Pepper
? Search for the password in Alex's roomScarlet didn't know the password but she said that I might find something useful in Alex's room.
? Search for CassidyI found the password on a little note, so I should speak to Pepper to venture further into the mine without blowing my cover. The note also mentioned the cultists I took out at the Shenandoah Visitor's Center. Sounds like I've done them a favor.
The disguise is working well, even allowing me to speak to some of the cultists and venture further into the mine. I should search for Cassidy deeper inside, but I must be careful to not be seen without my disguise or I'll have to do this the loud way.
? Find AlexI've found where they're keeping Cassidy. It's time I find Alex so I can make sure these tunnels are clear for Hugo to send out a rescue team to move Cassidy back to the Vault.
? Confront AlexI discovered a large chamber in the mines, which appears to be the main area of their big rituals. One of them is dressed differently, that must be Alex. I should speak to them.
? Clear the mine of cultistsSo much for blending in. I should make sure the mines are clear of any cultists so Hugo can send his men to safely extract Cassidy.
? Report back to HugoLooks like the mines are all clear now. Cassidy is secured, so she can be safely extracted by Hugo's men. I should go back to Vault 63 and report this to Hugo.


PCPC Once the objective to kill all cultists has been reached, and some but not all named cultists (Blaire, Scarlet, and Pepper) are killed, then the quest becomes soft-locked. Upon re-entering the cave, the quest will incorrectly think that no named cultists have been killed and place quest markers above each of them, even though those that you killed are still dead. To resolve the issue, exit and re-enter the world.[verification needed]