Complete the Underground Undercover quest in fallout 4. Find Patriot, get Liam's password, and complete the research project at Cambridge Polymer Labs.
Walkthrough
- 1From the doors leading to Advanced Systems in the Institute, head north, north-east, and follow a blue line down a ramp.
- 2Go past a stairwell and through sliding doors to the north, then east, then south to find the storage closet where Patriot awaits. Equip your Charisma gear for a potential speech check.
- 3Talk to Patriot about the Railroad, and he will lead you to a Synth named Z1-14.
- 4Attempt the speech check with Z1-14 if possible, then talk to Liam.
- 5Liam will state he needs a password and you must return to the Railroad to find it.
- 6Fast-travel back to Railroad HQ.
- 7Talk to Dez and tell her what happened.
- 8Activate the “PAM Mainframe Terminal” and select the entry “[Enter Institute Report]”.
- 9Talk to PAM, who will analyze the report and direct you to “Cambridge Polymer Labs”, located west of the C.I.T. Ruins.
- 10Fast-travel to Cambridge Polymer Lab.
- 11Upon entering, play along with the robot Molly's recruitment pitch and equip your Charisma gear for an interview speech check.
- 12During the interview, your answer to a single question determines your job. The sales coordinator position offers XP for an easy speech check.
- 13You will be asked if you want to attend employee orientation; this is optional but leads to a viewing area.
- 14After orientation, follow Molly into the Clean Room. Loot anything you wish before heading further in.
- 15Molly will announce mandatory overtime and lock you inside the Clean Room.
- 16Leave the Clean Room through a nearby hole in the wall as radiation is released.
- 17The quest objective is now to “Complete the Research Project” or find another way to escape. It is in your best interest to complete the project.
- 18Head into the “Experiment Room” and read “Ericka’s Terminal” to understand what happened.
- 19Familiarize yourself with the work area to the east, where the experiment will be conducted.
- 20To the left of the work area are two slots for agents, and to the right is where the isotope is placed.
- 21Read the terminal in the work area to learn that the required agents are “Gold” and “Lithium Hydride”, and you also need the isotope.
- 22Pick up the “Unidentified Agent 11317” from the start and place it in the agent container.
- 23Use the terminal to scan the agent, which reveals it is Hydrochloric Acid. Place it back in your inventory.
- 24Explore the lobby area and kill the Ghouls. More will appear, some from upstairs.
- 25Go to the south-west room, kill the Ghoul, and find a Hazmat Suit and “Unidentified Sample 3111” on the shelves.
- 26Go up a room to the west room, kill two Ghouls, and find “Unidentified Sample 413” on a table by the window.
- 27This room leads north into another room containing “Unidentified Agent 65” and the “Isotope Containment Terminal”.
- 28Hack the “Isotope Containment Terminal” (Novice) to open the door. This will trigger an alarm and a Glowing One will emerge.
- 29Take the north-east room on the lower level to access the isotope area. Equip the Hazmat Suit or use Rad-X as the room is highly radioactive.
- 30Kill the Glowing One in the radioactive room.
- 31In the corner of the isotope room, find a vial in a holder containing “U-238”, the required isotope.
- 32Head to the top floor.
- 33Enter a room to the east. In the closet, kill a Ghoul.
- 34On the deck in this room, by the ramp, find a skeleton with “Unidentified Sample 49” and a “Suicide Note” on the desk.
- 35Loot the room and head up the ramp.
- 36Avoid holes in the floor as you head north, then west.
- 37Drop down a third hole at the end of the southern passage.
- 38Kill the Ghouls in the room you land in.
- 39Check to the right of the terminal for “Unidentified Sample 611”.
- 40The desk in the middle of the room has additional items.
Tips
- Equip your Charisma gear before talking to Patriot and during the interview with Molly for speech checks.
- The “Unidentified Agent 11317” scans as Hydrochloric Acid, which is not what you need for the experiment.
- Be prepared for multiple waves of Ghouls in the lobby area.
- The room containing the U-238 isotope is highly radioactive; use a Hazmat Suit or Rad-X.
- Hack the “Isotope Containment Terminal” (Novice) to access the isotope area, but be aware it triggers an alarm and spawns a Glowing One.
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