A haunting tale of a family in extremis, based on her own novel

There really is nothing about the story here. The word haunting tries to evoke some tone, I think, but I have no clue what haunting means without more context. The family - is that the central character? I don't know what the story even could be and, just because it was a novel, doesn't mean that I would want to watch it.

Dave Trendall (Judge)

In extremis? Is that Latin? I didn't know what this meant and had to google it.
More about the story please... in plain English!

This really doesn't say anything about the story. It is interesting that it is based on the writer's own novel, but a logline is not the place for this information.