The Mechanist's Lair

The Mechanist's lair, formerly Robotics Technology Facility RB-2851, is a location and settlement that appears in the Fallout 4 add-on Automatron.

Background
The Mechanist's lair was hidden underneath a RobCo sales & service center which primarily sold and maintained terminals. Employees of the service center were told specifically not to interact with any abnormal crates, or else they would be "taken to see our friends below." In a storage room for the center, a large door which requires an M-SAT to enter leads into a large underground pre-War facility that was used for the development & construction of robobrains (jointly run with General Atomics and the United States Army Robotics Division). Part of it functioned as a pseudo-prison which housed prisoners, who were later operated upon to remove their brains. After wiping their brain of memories and passing assorted tests, the brains would then be housed in a robobrain head and mounted to any of a number of devices, including the bodies of a normal robobrain, controlling stretchers or even controlling operations inside the control center.

Sometime before the events of Automatron, Isabel Cruz discovered the facility while scavenging and took it upon herself to use it to create an army of robots to save the Commonwealth from anything which may hazard humans.

Layout
The lair is located on the map slightly north of the East Boston Preparatory School. It is behind an unmarked building, and near a warehouse by a bridge and a small wharf. A freight elevator inside the building (enter the door named "garage") will take the Sole Survivor directly to the underground location. Upon completion of the add-on, the location becomes a new settlement.

Settlement information

 * Despite being another interior settlement, this has significantly more customization options than Home Plate but will have a settlement building limit, unlike Home Plate.
 * The Mechanist's lair functions like an exterior settlement, in that settlers can be moved here, and supply lines can be established.
 * The following settlement crafting options are unavailable:
 * Food
 * Scavenging station
 * Garden plot
 * Recruitment radio beacon
 * Trading post
 * There are some patches of 'earth' on the top level in the northernmost corner, just outside the entrance to the facilities wing, where water pumps can be placed. Some can be placed on the workshop's level.
 * The crafting stations spread across the complex outside the construction area are linked to your workshop as if they are part of the settlement.
 * The upper levels of the settlement area are at the correct height to structure objects, making for easy development.

Inhabitants

 * The Mechanist
 * Sparks

Notable loot

 * Eyebot model - On top of some filing cabinets in the locked room with a skeleton hanging out the window, across from the generator.
 * Facilities director's holotape - Next to a locked (Novice) ammo box by the facilities management terminal.
 * Forfeiture terminal password - Located behind a desk as you enter the research wing, below the watch station terminal, gives access to the property storage lockup terminal.
 * RobCo sales and service center key - Directly to the left on a file cabinet when entering the lair. Opens a door and a safe.
 * A Mr. Handy model and the lead engineer's holotape are located on a desk next to the chief engineer's terminal in the quality control area.
 * A fusion core - Found in a generator after entering the Mechanist's lair. Lefthand side before the laser grid.
 * Perfectly preserved pie - Inside an Eat-o-tronic in the room with the button-operated platform and garage door.
 * A Vault-Tec lunchbox - By a skeleton at the end of the robot storage area (underneath a yellow eye protection poster). Another is located behind the generators at power substation B on a red stepladder.
 * Day Tripper - One floor above the desk which contains the Mr. Handy model. It's on the left desk which has a dead researcher in front of it.
 * Four Nuka-Cola Quantums.
 * One can be found in a crate after the fourth gate.
 * Two can be found in a crate on the raised left side when the ramp goes down, by Jangles the Moon Monkey and a cymbal monkey playing video games.
 * Another can be found in the room with the assembly lines.
 * Several robot parts models are scattered around throughout the interior.
 * In a locker just after the power substation A where the floor becomes flooded.
 * A second model is located on a shelf behind a Master-locked terminal in the research wing.
 * A third model is in the brain extraction area of the research labs near a terminal.
 * Mr. Gutsy model - Behind the watch station terminal desk just after entering the research wing.

Cells

 * Protectron model - Found in a surgical tray by a terminal in the cell observation area located above the cells.
 * Stealth Boy - Located at the end of the cell observation area on a box to the right of a hole in the floor.

Brain extraction area

 * Chief scientist's holotape - In the brain extraction area of the research labs near the cerebral reconditioning terminal, on a shelf under the table next to a robot parts model.
 * Medical terminal password - Can be found on a Quantum robobrain guarding the facilities management room.

Mechanist's headquarters

 * RB-2851 master control password - Given by the Mechanist during Restoring Order or taken from her body. Shuts down the security.
 * Mechanist's armor and matching helmet - Can be collected at the end of Restoring Order.
 * Protectron's Gaze - Carried by the Mechanist.
 * Mechanist's log - Found in the Mechanist's bedroom.
 * Drawing of the Mechanist - Found in the Mechanist's bedroom, on the table next to the bed.
 * Sentry bot model - Found in the Mechanist's bedroom, near the bed.
 * Overdue book - On a small shelf near the Mechanist's bedroom.
 * Mini nuke - On the shelf in the room at the end of the hall across from the elevator.
 * Eyebot pod schematics - On a table in the Mechanist's bedroom.
 * Spotlight schematics - On the blue terminals in the room at the end of the hall across from the elevator.
 * Burnt technical manual - Through one of the doors leading to the headquarters. Only three others are found, on Automatron NPCs.

Appearances
The Mechanist's lair appears only in the Fallout 4 add-on Automatron.

Behind the scenes
The doors in the lair open in a similar pattern to the ones by the original Mechanist in his lair at the robot repair center from Fallout 3. Although, unlike Fallout 3, the doors cannot be closed.

Bugs

 * After completing the final quest, leaving the building may cause the game to crash.
 * Fast traveling directly to another location, rather than leaving through one of the doors, may solve the issue.
 * There is a chance for a saved game that the Mechanist's lair cell may become graphically glitched when facing certain directions. Textures may pop in and disappear as you angle the camera and FPS drops dramatically when looking in that direction. There is no known fix for this issue so far. The only way to circumvent this bug.
 * Location and power armor locations can appear in the incorrect location on the map when inside the Mechanist's lair. This is corrected upon leaving the building.