The questline starts when you login, and doesn’t matter where you are located. The quest pops onscreen, asking you to come to Grommash Hold or Stormwind Keep. This questline is a follow up after the Antorus’s final boss defeat cinematic that shows Sargeras impaling Azeroth with his sword. Gallywix has discovered a mysterous substance in Silithus around the impact zone, and informs Sylvanas. The Bilgewater Cartel is sent to begin a mining operation there, and you are assigned to oversee those operations.