The Fog (1980), written and directed by John Carpenter.
Strange doings on the coast between midnight and one when fog rolls in and ghost lepers plague a cursed town.
That's about it. Good cast and many jump-shocks in this one, probably a worthy date film for the scary-but-not-very-gruesome market.
A clever setup: ghost stories on the beach. What are these films other than campfire tales in a new medium?
Available on Shout Factory Blu-ray.