One of the best ways to make a good horror film is to compel the viewer to empathise with a nervous protagonist. 2016's I am the Pretty Thing that Lives in the House succeeds at this so well that a very simple concept, a haunted house, requires only a simple plot and four characters. The climax features just two actors and an extremely simple special effect and is absolutely amazing.
Ruth Wilson plays Lily, who narrates the story, informing the viewer early on that she'll be dead before the end, thereby implying she's a ghost. We see her in life, though, in her occupation as a live in nurse for Iris Blum (Paula Prentiss), a retired horror novelist suffering from dementia so extreme she rarely speaks and rarely seems aware of who's in the room with her.
There are only two other characters--Mr. Waxcap (Bob Balaban) who manages Iris' estate and appears occasionally the check up on the two women, and Polly Parsons (Lucy Boynton), the ghost.
Another effective storytelling device the film uses is that it gives us clues to what killed Polly without fully revealing the cause. We learn she died naked and covered with blood but we never see this. In occasional flashbacks, we see her walking about the house wearing a blindfold and a man in the background out of focus. Did this actually happen? Or is it in Lily's imagination and less an actual event than a sort of performance of the issues underlying Polly's death? It's implied that after death, ghosts gradually lose the ability to piece together the actual events in their lives. Director Osgood Perkins does such a good job at putting us in Lily's perspective that the unresolved clues feel like a realistic mystery that forces the mind to come up with its own inferences. In films, as in many other forms of storytelling, the more you can get the audience to use their own imagination for you, the more effective your work of art will be.
Osgood Perkins is the son of Anthony Perkins, whom we see on a television in a clip from 1956's Friendly Persuasion rather than Psycho. This was Anthony Perkins' first film role, an American Civil War film starring Gary Cooper. The story focuses on a family of Quakers and I wonder if the younger Perkins chose this film to reference in I am the Pretty Thing that Lives in the House as a reflection of Lily's severe personality. We learn that, even though she's not required to, she always wears white to show the patient how clean she is. She has almost as much anxiety about a strange black mould as she does about the ghost.
The influences are unmistakable in this film. I can see the white room scenes from the end of Kubrick's 2001: A Space Odyssey and there's a very effective, eerie shot of Lily taken directly from David Lynch's Lost Highway. In terms of writing, though, the film recalls Shirley Jackson and Carnival of Souls in that it so perfectly entwines a fearful young woman's self-image and issues with supernatural phenomena.