This time we have an ambassador on the Enterprise to try to restore contact with a planet that was sent back to the dark ages a couple hundred years before. The inhabitants were originally theatre folk and ended up keeping and expanding the tradition of masks. They swap, earn, and buy masks based on their social status and jobs, never taking them off.
Picard, Worf, Deanna, and the ambassador go down first but lose contact with the Enterprise. Riker, Data, Pulaski, and two red-shirts end up going to look for them. There are also Ferengi wanting to establish contact with the planet.