A hole in a wall is what I kept thinking about once “The Whole Truth” was over. Two siblings find it in their grandparents’ house, and it opens onto somewhere it has no business opening. That is the premise, all of it. Wisit Sasanatieng builds the entire film on that single idea, and the Thai title, which translates roughly as “Haunted Hole Puzzle”, shows he knows it.

The setup is brisk. Pim (Sutatta Udomsilp) is a popular cheerleader. Her brother Putt (Nattapat Nimjirawat) is a bit of a social outcast who wears a leg brace, and the film never says why. Their mother, Mai (Nicole Theriault), raises them alone and has just been promoted. Then comes a rainy night, a car accident, a coma in intensive care. A man appears at the door and says he is their grandfather, Phong (Sompob Benjathikul). At the hospital they meet their grandmother, Wan (Tarika Thidathit), who calls Putt “Krit” by mistake and insists the teenagers move into their mother’s old room because, she says, they lived there as children. Neither of them remembers it. Phong explains that Wan has dementia and asks them not to take her oddities to heart.

Dementia is a convenient label, and the film knows how to use it. It blurs symptom and haunting until you cannot tell which one you are watching. Is Wan confused, or is the house? Abishek J. Bajaj’s script holds that question open for a good while, and these early scenes are the most unsettling in the film. Pim brings her grandfather to look at the hole. He sees nothing. Neither does Wan. They decide the children are lying, and Phong storms off. Wan stands looking at a blank patch of wall where a clock used to hang, then announces bedtime. Nothing supernatural happens in that moment, and it is still colder than most of what follows.

Through the hole Putt sees a second house, much like the first but rotting, and a dark-haired figure moving inside it. The hole closes up, then comes back. Wisit is patient with all this, and he lets a scraping noise reach us before any picture does. The best sequence arrives when Putt’s schoolmate Fame (Sadanont Durongkhaweroj) is in the house, still leaning on Putt over a video he holds against him. Fame hears nothing and sees nothing, even when Putt looks through the hole and finds a child with a black, grotesquely swollen face and dark liquid running from its mouth and nose. Then Fame leans in to look himself and comes away with a bloody nose, and he blames Putt for shoving him. It is a nasty little scene, because the logic of the house turns against the one person telling the truth.

The cast is solid without being showy. Sompob gives Phong a short fuse that hints at more than the dialogue admits, and Tarika makes Wan’s lapses sad before they turn frightening. Sutatta and Nattapat have the harder job, since the script asks them to react to things nobody else can see, and they stay credible throughout. Fame is the least developed figure: a bully who exists mainly to push the plot along.

The film gets into trouble when it tries to grow. It wants to be a story that spans generations, and one early review argued that it lacks the nuance such a story needs. I agree. Family secrets, a haunted house and a thirst for revenge on Phong’s side (one summary calls it a misguided quest) all compete for the same running time. The pace wobbles. Some stretches drag, while others hurry past material that needed room, and the last act feels thinner than the mystery that led up to it.

The film reached Netflix on 2 December 2021, in Thai with English subtitles. Reaction was divided. Some viewers on Rotten Tomatoes call it shockingly underrated and say the premise and its emotional core deserve a watch. That is generous, but I see where they are coming from. The hole is a great hook, and the film is at its best when it trusts it.

I would not call this a great film. It has one great wall, a handful of scenes that earn it, and an atmosphere and cast that carry it further than the plot does. If you want a tidy mystery, look elsewhere. If you can forgive a muddled ending for the sake of that wall, it makes a decent evening.