The City and the Stars is a main quest in Obsidian’s The Outer Worlds.
Your task is to help Phineas get dimethyl suffoxide in Byzantium from Minister Clarke.
Here’s a walkthrough of The City and the Stars in Outer Worlds.
Meet Carmen Imagawa
Your first objective is to meet Phineas’ contact at the Byzantium landing pad.
As you’ve gotten the Navkey from Phineas, you can immediately fly there. Talk to Carmen who is nearby.
Introduce yourself to her.
Look for Minister Clarke’s guard (optional)
There’s an optional objective where you meet the guard to Minister Clarke first.
Take the elevator to the main area of Byzantium.
The guard’s location is nearer.
Go to the bar and you’ll find him here.
Talk to Guard Mayfield and suck up to him first.
Next, keep offering Spectrum Vodka to him.
When he’s drunk, you can use medical / persuade to keep him going.
Get the minister’s estate key
Mayfield will walk to the toilet once he’s drunk. You’ll see him sleeping.
Close the door and loot the key from him. If there’s a bug where you can’t loot, just kill him and loot the minister’s estate key.
Find Minister Clarke
Head to the minister’s place and you’ll be stopped by the guard.
If you wish to avoid bloodshed, convince him that you’re here for a delivery.
You need to first take the parcel. Head to the Halcyon Parcel Service which is located near the basement tunnel.
Inside the area, you can actually persuade one of the officers to hand over the parcel for delivery.
Otherwise, you would have to lockpick into the mail room.
Enter the minister’s residence
Once you have the parcel, you can probably talk to the guard to let you in.
Another way is to unlock the door using the estate key you got from Mayfield, but this one will result in a fight.
We chose to just barge in (which means you can skip the entire parcel part) but you’ll end up decreasing your reputation and will have to kill the guards.
Having a bad reputation means you can’t complete some quests by the Board as the NPCs will try to kill you.
Talk to Minister Clarke
Look for Minister Clarke and talk to him.
Ask him about the dimethyl suffoxide. Apparently he has nothing to do with it since he has been on house-arrest for a long time.
Chairman Rockwell is behind this.
Ask him for more info on how to get into the minister’s office.
You should get the key from Clarke.
Head to the HHC building
Now, go to the chairman’s office which is in the HHC building.
Inside, there’ll be plenty of guards. If you don’t have a Board ID, then you’ll have to go through the guards.
After you’re done with the guards, enter the building.
Inside the building, there’ll be more guards to deal with.
Once the area is secure, take the elevator up.
Deal with more corporate guards again.
Look for the terminal
To get to the terminal, you have to go a longer way around through the side.
You should see the terminal here.
Use it to send Minister Clarke’s message to earth (as part of a side quest).
Also, view the messages on the terminal.
You’ll watch a planned broadcast by Chairman Rockwell, saying they will freeze the colony to save cost.
Print the keycard for the Ministry of Accuracy and Morale.
Go to the Ministry of Accuracy and Morale
After learning that the dimethyl suffoxide is kept in the Ministry of Accuracy and Morale, head to the building which is beside the HHC building.
Inside the building, more guards await.
Take the elevator to the lab area.
Look for the dimethyl suffoxide
Down in the lab, you have to find the dimethyl which is marked on the map with the green objective symbol.
It’s kept in the hibernation lab.
Find a way to the hibernation lab. There’s one way through the upper floor.
Jump down to the hibernation lab. You can do so by jumping on a small platform at the right side and subsequently jumping down to the lab area.
To get the dimethyl, use the terminal.
You can either transfer 100% of just 26%. If you transfer 100%, the patients will die but you’ll have sufficient amounts for Phineas.
Transferring 26% means you will spare the lives of those hibernating but you won’t have enough for Phineas.
It will probably alter the ending. We chose the 26%.
After transferring the suffoxide, steal the canister.
Return to Phineas
Go back to Phineas at his lab.
Talk to him and he’ll say it’s not enough. It can only revive a handful of settlers.
That being said, you can convince him to jumpskip the entire Hope ship to the Terra 2 orbit.
Also, you can tell him that Adjutant asked to plant a tracking signal in the lab.
The quest ends here.