This is an odd film. A father, John James (Kevin Costner), his teenaged daughter and young son move into an old house out in the country. There's a strange hill on the property that turns out to be an Indian burial mound. The daughter, Louisa, isn't too happy about the move and soon she starts acting strangely. She sleepwalks. Then the pet cat disappears and is later found dismembered--and a babysitter vanishes as well. We learn that there are creatures from Indian mythology that supposedly live under the ground. They are an all male race and take a human woman to breed the new generation. You guessed it--this turns out to be Jame's daughter.
The special effects are great, particularly the weird creatures that come out of the burial mound, and it has a very dark, unhappy ending, which is untypical. I recommend this but be warned that the first hour is very slow-moving.