The trading exchange in the city of Requiem on Hima, run by Orions and Andorians, where couriers pick up work and Burnham is betrayed within hours of reaching the future.
The Mercantile is the commercial hub of Requiem, seen in the Discovery third-season premiere That Hope Is You, Part 1. In the dilithium-starved galaxy of 3188 it is where couriers trade cargo and take jobs, under the eye of Orion and Andorian managers and their armed guards.
Cleveland Booker brings the newly arrived Michael Burnham there, promising help in contacting her ship. Instead he hands her over in exchange for dilithium, and she is dosed with a drug that makes her babble the truth about her origins and her antique equipment.
When the managers turn on Book as well, the two fight their way out together, grabbing dilithium and using portable transporters to hop across the landscape with their pursuers close behind. The episode's picture of the exchange is the audience's first look at how trade works after the Burn.