Fallout 3

Story Related and Unmissable

This is a 3 part trophy as you have to get through 2 further Quests after finishing "Walking With Spirits" before you will be given the "A Meeting of the Minds" Quest:

Part 1: Hearing Voices

After returning to the Cathedral go inside and talk to Nadine about her Mother. Ask her to fix your scar then ask what she knows about where Jackson is hiding, to which she’ll reply that she followed him and will you give you the key to get in. After speaking to Nadine, talk to all the other named people in the Cathedral then exit the building. Now you have to return to Desmond who will be really peeved that you returned without any info. He will send you packing and tell you not to return until you have the answers he seeks. After exiting the Mansion, Fast Travel to the Cathedral and make your way down to the Wrecked Seatub and enter it.

Once inside the Seatub make your way through the winding tunnels by following the flaming torches to Jackson’s praying spot. When you find Jackson, he'll converse with you for a bit about what he's doing down there then he'll leave. After he has left go to the Holo-Projector on the table in front of you and talk to the "Brain", who will bemoan how useless the people from the Cathedral are and how he hopes you will do better. The "Brain" will tell you that Desmond has a Jamming Device that's blocking his transmissions and wants you to destroy it. This Quest will end during your conversation with the "Brain".

Part 2: Thought Control

After the above Quest has finished, return to Desmond and tell him what has happened. He will then tell you that the "Brain" actually belongs to Professor Calvert, the Calvert Mansion's last pre-war owner. Desmond will also tell you that they’ve been feuding for over 200 years. Desmond wants to silence the Professor’s transmissions by placing a Jamming device on the highest point in Point Lookout, which just happens to be the local Ferris Wheel.

When you get to the Ferris Wheel, you will have two choices:

1. Side with Professor Calvert.
2. Side with Desmond.

For the purposes of this guide we'll be siding with Desmond as it's the least buggy option.

To plant the Jamming device press on the parked Ferris Wheel seating pod. After planting it you will have a few seconds in which to Fast Travel back to the Mansion or else you will have to fight off several waves of Tribals. Once you've arrived back at the Mansion it will promptly explode and be reduced to a pile of rubble. After you've picked yourself up, head towards the ruins. The Quest will end once you approach the entrance to the ruined mansion.

See here for a list of potential bugs and how to avoid/fix them: LINK (credit to the Fallout Wiki for the link).

Part 3: A Meeting of the Minds

After entering the Mansion Ruins, head to what was the Entrance Hall and find the hatch to a Bunker that was previously hidden from view. Inside the Bunker you will find an extremely annoyed Desmond who will rant and rave at you for while, then eventually he will say that it's time to settle things once and for all! Eventually he will tell you that Professor Calvert's Brain is hiding in the Bunker under the Point Lookout Lighthouse and that he's heading there now and to follow him.

Once inside the Lighthouse a hidden staircase will open in the floor in front of you, follow Desmond down them and help to destroy all the Sentry Bots, Robo-Brains and Turrets. Taking out the Turrets is easy because most are controlled from nearby hackable Terminals and Desmond will destroy the rest. After a short while you'll enter the central chamber where Professor Calvert's Brain is hiding and he/it will call you over and try to persuade you to kill Desmond.

You now have to two choices:

1. Kill Professor Calvert.
2. Kill Desmond.

For the purposes of this guide we will be killing the Professor.

Killing the Professor couldn’t be easier as all you have to do is use your most powerful weapon to shatter the container his Brain is in. After the container is destroyed, Desmond will congratulate you on killing the Professor and give you the key to the Reward Vault. This contains stacks of ammo and at least one unique weapon. The trophy will pop during the conversation with Desmond.

After cleaning out the Reward Vault, return to the Boat and speak to Nadine who will inform you that she's now in charge of the Duchess Gambit. After learning of what has happened to Tobar, go to the Engine Room and speak to him then kill him. Now strip his body of everything useful and retrieve a valuable item of yours from the nearby table. You can now return to the Capital Wasteland and speak to Catherine, she will give you 10 Refined Punga Fruit and 300 caps for finding her daughter.