You know a director has a knack for visual terror when he doesn't just kick off his movie with a voice comparing a ghost to "an insect trapped in amber," but also shows a boy dropping to the bottom of a brackish pool. We immediately plunge into a blood-tinged limbo.
For connoisseurs of intelligent horror, Guillermo del Toro's The Devil's Backbone, a ghost story set in an isolated boarding-school-cum-orphanage during the last days of the Spanish Civil War, has an enticing combination of ingredients, with imperiled innocents and political upheaval at the top of the list.
Inevitably, it's disappointing when the witches' brew turns out to be thin. But you may find that images from this movie clamber back into your memory weeks after you see it, and give your spine a chill.
As well as a repository for children of Republican politicos and soldiers, the Santa Lucia School has become a secret rest-stop for Republican agents and a hiding place for gold earmarked to back the Republican cause.
The hero, Carlos (Fernando Tielve), a 10-year-old orphan (he doesn't know, though we do, that his father is dead), faces all the usual getting-to-know-you pains of life in an all-male academy, whether he's joining the intense conversation and competition over comic books, knickknacks and marbles, or figuring out exactly where he stands with the junior-division alpha male in residence, a scrawny guy named Jaime (Inigo Garces).
Carlos also must confront unusual challenges to prepubescent sanity. In the center of the courtyard there's an enormous unexploded bomb; it's been defused, but one boy says that if you stick your ear to it, "you'll hear ticking." And soon he meets the wheezing specter of "the one who sighs" - probably the ghost of a boy named Santi, who disappeared the night the bomb dropped. Carlos happens to be sleeping in Santi's last bed.
Director del Toro has learned two big lessons from Henri-Georges Clouzot's Diabolique. The first is the skin-crawling qualities of dankness. The scenes set in a basement cistern are eerie because they are, literally and metaphorically, so liquid. Reality seems to decompose when we see the ghost through a watery haze; he has a head wound that never stops oozing. It's a horror-maker's coup - an image of unsettling melancholy.
The other lesson is that a seedy childhood setting like a hard-up boarding school intensifies the creepiness of adults. The one-legged headmistress, Carmen (Marisa Peredes), respects and platonically loves the impotent old professor Casares (Federico Luppi). But she shares her bed with a callous former student, the handsome young caretaker Jacinto (Eduardo Noriega). He is courting the fetching cook Conchita (Irene Visedo), who dreams of running a farm with him in Granada. But Jacinto's true love is for money.
With lust, greed, betrayal and dashed hopes rebounding through the ranks of the grown-ups, it feels both surprising and fitting when the story veers off into the territory of Lord of the Flies.
The Devil's Backbone may be thin, but it's also sharp, like a stiletto.
Starring Eduardo Noriega, Marisa Paredes, Federico Luppi and Fernando Tielve
Directed by Guillermo del Toro
Rated R (violence, adult language, sexuality)
Released by Sony Pictures Classics
Running time 109 minutes