Pilot Tom Gregory (Robert Hutton) lands his private plane in Los Angeles and is shocked to discover that the city is surrounded by a thick fog and that it appears to be nearly deserted.  A chance meeting with a professor named Galbraith (Robert Burton) and his two daughters (Susan Hart and Judee Morton) leads the group to a television station where they watch a news report about how Los Angeles has been surrounded by a “hardened fog.”  No one can escape the fog and no one can escape the Slime People, reptilian humanoids who have ascended from their underground lair and declared war on the surface world.  There appears to only be, at most, six Slime People but I guess that’s all you need to conquer Los Angeles.

The Slime People is a Z-grade horror film that features a lot of stock footage, monsters that would not be out of place in a Jon Pertwee-era Doctor Who serial, and an out-of-control fog machine.  The fog machine is actually the star of the show.  There’s so much fog in this movie that it’s often impossible to see the actors or the Slime People.  It’s a shame because, considering that the production ran out of money after 9 days and the majority of the actors were never paid, the Slime People costumes are not that bad.

Along with the fog and the costumes, the other memorable thing about The Slime People is that none of the survivors seem to be particularly upset about any of the horror that they’ve just experienced.  One young soldier (William Boyce) takes the time to ask one of the professor’s daughters if she’ll be available to date once the crisis ends.  It’s a tribute to the American youth of the 1960s that not even an attack from underground dwellers could stop date night.