Once again you arrive at different locations depending on who you arrive with: Ava in front of the SSC station and Sid on the roof of the tavern.
You receive a message from Ava; she suggests looking in the Nine Worlds Tavern for your mystery person.
Primary Goal: Find Tracer Tong.
According to Dr. Nassif, Tracer Tong is the leader of the ApostleCorp cell in Trier and the only one who can contact JC. He is a brilliant technologist and has a long history with the Dentons, pre-dating the Collapse.
Pick up a datacube in the square to snag a map of Trier. Go through the passage to the right of the SSC station. Listen to the conversation between the Panzerwerks Techs. Search the boxes to the right for an ammo clip. There's an ATM on the other side. You can stand against the wall on the ATM's right side and hack it without being detected by the camera.
Enter the QueeQuegs coffeehouse. Speak with the manager to ask about the location of the tavern--looks like the manager has a lawsuit against Pequod's, which shouldnt be too surprising. He offers a secondary goal: search the evidence room at the SSC station to find out why the QueeQueg's manager's lawsuit has been delayed (his reward is 200 credits).
Secondary Goal: Coffee Wars - Investigate Lawsuit.
Talk to the NG Resonance if you wish. Next speak with David Kurczec, a representative of the Omar black market. He says you can meet the Omar in the Der Blutende Rabe curio shop located upstairs from the Nine Worlds Tavern.
Secondary Goal: Meet Omar.
Open the door to Kurczec's left. It leads to a storage room; an escaped Greasel guards here. Grab the items from the desk and use a multitool to open the safe, which contains 200 credits, a glass destabilizer weapon mod, boltcaster, energy cell, and a spiderbomb.
Return to the Trier streets. Go left from the ATM area and continue left past a ladder to find the Nine Worlds Tavern. Enter the tavern (you can go up the ladder to the helipad, where Sid lands, and find a multitool two-pack and an energy cell). Go through weapons check and then up the stairs into the Curio Shop (you should have the keycode if you spoke with Kurczec). Talk to the Omar trader. He sells a black market biomod canister (which you must locate at a drop site), some scrambler grenades, and multitools.
Secondary Goal: Black Market Biomod - Find Canister.
The black market biomod canister can be retrieved from the Black Gate ruins, west tower, top floor, in an unmarked silver foot locker.
While in the Curio Shop, search behind the boxes in the back corner for some ammo, mines, and the assassin pistol.
Proceed downstairs into the tavern. Talk to Sid Black at the bar then go to the left and listen to the conversation between the two tavern patrons. Listening to their conversation opens up a secondary goal: investigate the Nur Gewehre shop for a cache of weapon mods.
Go through the door to the bar's right. Enter a conference room and speak with Ava Johnson. A datacube on the table contains a map of Trier (useful if you arrived with Sid). At the end of the table is Tracer Tong. Speak with him to complete an objective and receive new orders. You need to access ApostleCorp's Black Gate lab via an entrance on the east side of the ruins on the second floor. A keypad hidden behind some creates can be used to open a false wall. Tong also wants you to find Her Holiness at ApostleCorp's Black Gate lab.
Primary Goal: Black Gate - Find Lab Entrance; Primary Goal: Rescue Her Holiness.
Before leaving the tavern, search the back room by using a multitool to unlock the door. You'll find 400 credits in this office. Return to the Trier streets.
As you exit the tavern, you're contacted by Dumier and receive a secondary goal. You need to talk to Dumier at the SSC station.
Secondary Goal: Talk to Chairman Dumier.
Exit the tavern to the right and notice the protected glass up ahead. Those are the stolen weapon mods. Use a weapon with a silencer and glass destabilizer when no guard is around to destroy the glass. Inside you'll find increased range and damage mods, ammo, and a sniper rifle and shotgun.
Continue around the corner and find two Panzerwerks Techs bullying an order seeker. Defend the seeker or allow it to play out. Continue back to the square and enter the SSC headquarters.
Speak with Vera Maxwell to the right of the front desk. You can follow her into her office and steal some ammo and a multitool. Continue into the evidence room. You can use three multitools to open the door or use a weapon with a glass destabilizer and a silencer to shoot the protected glass. If you're a hacker, there's a security computer on the right that can be used also. Search the shelves for a biomod canister and an assortment of grenades and mines. Check the datacube for the QueeQueg's manager's lawsuit evidence.