Star Trek: The Next Generation: Masks

The Enterprise™ journeys to Lorca, a beautiful world where the inhabitants wear masks to show their rank and station. There, Captain Picard and an away team begin a quest for the planet's ruler and the great Wisdom Mask that the leader traditionally wears. Their mission: establish diplomatic relations.
But Picard and his party lose contact with the ship, and Commander Riker leads a search party down to the planet to find them.

Both men are unaware that their searchs are part of a madman's plan. A madman who is setting a trap that will ensnare both landing parties, and leave him poised to seize control of the awesome Wisdom Mask...

And the planet Lorca itself.