Obtain: Melissa at the Great Khans Camp
Offer your services to Melissa at the Great Khans camp west of Quarry Junction to get this quest (Picture 1-2). The young woman will then ask you to find a suitcase containing drugs for sale. To retrieve this suitcase, go to Sloan and go upstairs to the main building (Image 3).
Unfortunately, the suitcase is empty, get out of the building and ask Chomp Lewis about it (Picture 4). You will learn that a certain Tyrone is trying to grease his paw on the backs of the Khans and their dope deliveries. Go to the NCR camp in Primm to talk a bit with this Tyrone and convince him to give you the goods (Picture 5). All you have to do is go back to Melissa to end this quest (Picture 6).
Alternate outcome: Kill Tyrone to recover the goods