Symbiosis

The Enterprise saves four people from a crippled freighter: two Brekkians, Sobi and Langor, and two Ornarans, T'Jon and Romas. Oddly, they seem more worried about their cargo of felicium than their dead crewmates. Felicium, produced only on Brekka, is said to be the sole treatment for a plague that once swept Ornara, and the Ornarans pay for it with everything they have. When Dr Crusher examines the Ornarans, she discovers that the plague was cured long ago. Felicium is an addictive narcotic, their symptoms are withdrawal, and the Brekkians know it. Crusher wants to tell the Ornarans the truth, but Picard insists that the Prime Directive forbids interference. In the end he takes a quieter course: he refuses to supply the parts the Ornarans need to repair their freighters, so the trade must soon end, leaving both worlds to face a painful but necessary change.