You unlock the achievement by reconciling the differences between mother Olivia and daughter Minnie during the final main quest mission, The Ambrose Intersection. You will arrive at this mission through story progression, but there are four possible endings. This achievement relates to one of those four endings: Achieve a compromise to the Family Reunion achievement.
The other three endings are:
1. Take Minnie's side by activating the reactor leading to the Greenlight protocol achievement. However, the achievement can be earned elsewhere so this ending is not required for a 100% completion.
2. Take Olivia's side by destroying the synthesizer leading to the NDA protocol achievement.
3. Take neither Minnie's nor Olivia's side. Kill Minnie before you acquire the journal, causing Lucien to appear. Activate the reactor leading to the Greenlight protocol achievement and deliver the journal to him leading to the Postman achievement.
To have access to all four endings, make a save as soon as you get to The Red Tape of Command main quest mission. This is the second to the last main quest mission where you must retrieve a journal. The Postman ending requires a specific action to be performed before the journal is retrieved. That action precludes obtaining this ending. So, to get both this ending and the Postman ending on a single playthrough, make a save file at the decision point before the journal is obtained.
When you start the Ambrose Intersection mission for the purpose of getting this achievement, make sure you have persuade at 150. A high persuade is not required for the other three endings.
Basic persuade need not be high. My character's basic persuasion was only 52 (with very high intelligence & temperament & good charm. However, I boosted persuasion to 153 as follows:
Cashier, Sub-Grade: +1
Wearing the Chimaera +20
Wearing the Nice Hat +14
Caffeine Drink +5
Felix wearing Dialog Skills +5 armor with Dialog skills +10/Leadership Skills +10 kit & persuade +5 helmet: +26
Parvati wearing Dialog Skills +5 armor with Dialog skills +10/Leadership Skills +10 kit & persuade +5 helmet: +25
Felix Perk Bonus Support Persuade: +10Tip
: If you include a caffeine drink in the inhaler, you can instantly get Mind +1 resulting in Persuasion +5 by pressing
as you approach a character with whom you are to have a dialog.Note
: The DLC introduces the Improved Silver Tongue armor mod kit to the game. It is fairly common as loot and is also available at certain vending machines. It provides Dialog Skills +10 compared to the Silver Tongue Kit in the base game that only provided Dialog Skills +5. The Chimaera and the Nice Hat are acquired when you get the Well Dressed achievement in the base game.
If you can't get persuade to 150, you can reset your skills aboard your ship in order to meet this prerequisite.
With 150 persuasion, go to Minnie at the Ambrose mansion. There will be mission objective markers on both Minnie and Olivia so make sure you follow the objective marker for Minnie at the mansion and not Olivia at the Synthesis & Manufactory Center. As you approach your objective be prepared for the dialog to start abruptly. If you need to, ingest a caffeine drink when you are a few meters away. As you begin the dialog with Minnie, immediately suggest a compromise as soon as the option becomes available. The dialog differs depending on what your character has discovered during the game. Be positive and work towards reconciliation. This is a sample dialog, yours might differ:
--What if you & your mother joined forces to cure the marauders.
--[Persuade 65] If the marauders don't get a fix, they'll just rampage across the galaxy.
--[Persuade 100] Why not give her a chance, she's been involved with Adrena-Time since the start.
--[Persuade 150] The Adrena-Time project failed, you couldn't have saved it.
--Opportunities present themselves every day, your Gorgon will come.
--This isn't failure, this is a second chance to work with Olivia.
Minnie will say that maybe her family deserves a second chance. At this point, you will have three options for the Ambrose Intersection Mission:
1. Restore power to the Adrena-Time reactor
2. Activate the NDA protocol
3. Find a compromise between Minnie & OIivia
In other words, if you make a save file here, you can use it to get three of the four endings. If you want the NDA protocol, just walk up the stairs to your right and left and go to the terminal behind Minnie. She will protest, but you can use the terminal and activate the NDA protocol. However, to complete the compromise, we must go to Olivia. Return to your ship and go to the Gorgon Landing Pad. From there, go to the SMC facility. If you had befriended PAM before, talk to her. She will be right inside the entrance to the facility and will again lead you through the facility helping eliminate hostiles. She will stop next to the elevator that leads down to Olivia. Alternatively, you can make your own way through the facility, eliminating hostiles as you go. When you exit the elevator, use a caffeine drink if you need a +1 mind boost, open the bay door & a smaller door in front of you, and go forward to trigger the dialog with Olivia. Yours might be slightly different but here are some possible dialog choices leading to reconciliation:
--Whoa, hold on! I'm here to make peace!
--Let's take it down a notch.
--Your daughter's agreed to a compromise.
--[Persuade 45] You don't. You just have to trust me.
--She said you were invited to tea?
--So you'll work with Minnie.
There are differing scenarios that work. Nevertheless, providing that you choose positive responses, eventually the other person will acquiesce and the achievement pops. The Ambrose Intersection Mission is complete at this point. You get a green check mark in the reconciliation option and red checks in the other two options. You can return to the mansion for a short dialog with Minnie and Olivia to finish the DLC story.Note
: As mentioned in the comments, some people do not lock the achievement upon completion of the Ambrose Intersection Mission but later upon return to the mansion. Note2
: I was going to do a little more experimentation before posting this guide. However, I have gotten a couple of PM's asking for hints so I thought I'd post this immediately. If you have any additional detail, post in the comments. I, myself, will continue to experiment and update the guide where appropriate.
Edited 12Sep2020: As promised, I have continued to experiment. Thanks to JUSTTHINKSD
& Scotty x360a
. Their comments are reflected in the most recent edit. I have now included sample dialog choices to assist in the conversations with Minnie and Olivia.