Completing the armory of the Mistress, the Vault Dwellers achieved the rank of seeker. However, in order to become a Mistress of Mystery, they need to complete a Mistress-rank mission. Cryptos can issue one.
- Listen to the Order of Mysteries - Rank: Seeker holotape.
- Accept a Mistress-rank mission from Cryptos and listen to the holotape it dispenses.
- Travel to Pleasant Valley Ski Resort and enter Brody's room.
- Pick the lock or find Brody's room key in a duffle bag at the motel building.
- Read the Pleasant Valley intranet memo, found in a footlocker in Brody's room.
- Access Brody's terminal and read the entries.
- Select the "Dispense SIPHON holotape" entry to complete the quest and start The Mistress of Mystery.
- The quest starts off with the Order of Mysteries - Rank: Seeker. After listening to it, players have to access the Cryptos and pick a Mistress-rank mission. The only one available is the infiltration of Pleasant Valley. After listening to Order of Mysteries - Pleasant Valley, it's time to head to the Pleasant Valley Ski Resort.
- Once there, the player has to learn how the raiders learned so much about the Order of Mysteries. This is achieved by hunting down the notes scattered across the resort, which will eventually point to a raider called Brody as the source of their intelligence. His room is located in the cabin near the raider arena.
- Brody's room contains a terminal with the target holotape. The player can either lockpick the level 3 door or read the Yo Brody entry on the nearby terminal, which will place a marker on the room key needed to access it. Once inside, there's one more hoop to jump through: The terminal has a level 3 password. If hacking it isn't an option, then the player will have to either lockpick the footlocker by the bed to find a note with Brody's password on it or reset the passwords using the computer in the main lodge of the resort.
- The player then has to collect the Siphon holotape from the terminal and use it to log in as Olivia at Cryptos.