Citadel: Garrus is obtained from Captain Anderson, shortly after your first meeting with the Citadel Council. You first need to speak with Harkin, down in Chora's Den in the Wards.
The next step is the Med Clinic, down in the Wards. You engage in a firefight but are able to save the attending physician, Dr. Chloe Michel. She tells of a quarian who offered information relating to the geth. She also mentions that she referred her to Fist, an agent for the Shadow Broker. Garrus also mentions Wrex, leaving you with a choice; locate Wrex first, or Fist.
Mass Effect: Infiltrator·The Final Hours of Mass Effect 3·Galactic Codex: Essentials·Mass Effect Galaxy·Revelation·Ascension·Retribution·Redemption·Evolution
Soundtracks
Mass Effect Original Soundtrack·Mass Effect 2 Original Videogame Score [Atmospheric·Combat·Kasumi's Stolen Memory·Overlord·Lair of the Shadow Broker] ·Mass Effect 3 Original Videogame Score [Extended Cut·Citadel·Leviathan] ·Mass Effect: Andromeda - Original Soundtrack
