The Black Mansion

This story is based in Europe. All the words, foods and phrases are all real German things. I know them from my dad who knows multiple foreign languages including German and lived in Germany for 3 or 4 years before he married my mom. He's pretty cool in my opinion. now to the description.....
in 1347, a rich, greedy family in Europe dies of what you probably know as the "black death".
Now, present day, a family moves into this house. The son experiences frequent nightmares of his family dead on the floor as he arrives home from school. His parents, very skeptical, put him in therapy.
a couple of months later, his parents start having the same dreams and wake up with scratches and scars.
as they continue to shake it off and try to find reasonable explanations for the occurrences, they get worse. and worse. and worse.