Some historical fiction is set during an important moment in history. The House of Dies Drear is a little different. It is set during an important moment in history – the Civil Rights Movement, but this isn't explored. The characters are too busy trying to find out the secrets of pre-Civil War past that will help them understand the mysteries of the present.
This is where things get Gothic. Much of the mystery surrounds the house – is it, or is it not haunted? Just about anytime a haunted or possibly haunted house (especially with secret passages) is a central focus of a story, it's a Gothic story. Gothic fiction and Historical fiction often go hand in hand, because we are haunted by our histories, our pasts. One might even say that slavery is the ghost of United States history.