Note: You must have first completed up to and including Priority: Palaven to unlock this mission as well as purchased the DLC pack Leviathan from the respective store of your choice.
To access this mission, first visit your private terminal and open the mail from Hackett asking Shepard to assist Dr Bryson. You are asked to visit her labs on the Citadel so head straight there. Upon arrival, dock and select Bryson’s Lab as your destination.
After the cutscene, select the datapad in front of you to get some more information about Leviathan and how to find it from EDI. Your task is to search for clues around the lab that will enable you to uncover Leviathan’s secrets.
Go over to the Galaxy Map to have EDI explain this for you. This will open up the rest of the lab for your perusal. First, head out of the door directly behind you into the garden. On some crates in the corner is the Pistol Cranial Trauma System Mod I.
Continue down the garden and look in the barrels to the right to find an SMG High-Velocity Barrel I. The Cranial Trauma mod is self-explanatory: it increases headshot damage. The High-Velocity mod is very useful as it enables greater armour-piercing than the piercing mod though this comes at a price as your weapons are heavier. Some high-velocity mods also add damage.
At the end of the garden under a tree lies the Pistol Ultralight Materials Mod I . Again, its name gives away its use. Yes, it makes your weapons lighter (useful for power-based characters.)
Head back into the lab via the nearby door and go over to the computer right in front of you. Click on the video log to have EDI suggest that you look for Rachni ship data. Fortunately, the console in front of you provides that data. EDI will add the Rachni Activity Filter to the map.
If you touch the picture next to it, you will find a prelude of what is to come. Feel free to explore other objects not directly mentioned in the guide. That shiny board at the back of the room is your next port of call. EDI will add the Creature Sightings Filter to the map afterwards.
The large rock to the left will add the Locations With Element Zero Filter as well. You also unlock the SMG Mass Pulse Recoil System Mod I by doing so. It drastically reduces weapon recoil so is great for SMGs with heavy recoil like the Blood Pack Punisher.
Turn around and go to the computer near the Sovereign fragment. Play the video log and after, access the Encrypted Data. You need to find something “close to his heart.” Head up the stairs on the right and examine the picture on the desk.
Go back to the Encrypted Data and EDI will add the Reaper Activities Filter to the map. Examine the Element Zero filter and EDI will identify five systems where Dr Garneau could be. In order to unlock the trophy/achievement Conspiracy Theorist you must narrow the search.
Choosing Reaper Activities narrows it to three systems and finally, choosing Creature Sightings restricts it to one system. What are you waiting for? Let’s go! Go outside and get in the Rapid Transit to return to the Normandy.