Mass Effect 2 - Lair of the Shadow Broker
First mentioned by TheVampwizimp
Widely considered to be the best of the Mass Effect DLCs, Lair of the Shadow Broker is set two years after the events of Mass Effect: Redemption. Commander Shepard goes on a mission to help his former squadmate Liara T'Soni find the Shadow Broker, a clandestine dealer in information. Decisions from the original Mass Effect actually impacted the gameplay in Shadow Broker, and completing the DLC gives Shepard access to the Shadow Broker's Base and the information stored within.