Engaging, confusing, and completely sui generis, the veteran animators' first feature in 20 years is better described than deconstructed, and probably better watched than described.

Time, space and mortality operate on no earthly schedule in the dimly lit, hand-crafted twilight world of “Sanatorium Under the Sign of the Hourglass” — so it’s fitting that this dizzying stop-motion vision seems to operate on its own temporal laws. The first feature in nearly two decades from cult animators the Quay Brothers clocks in at just 76 minutes, but watching it feels both infinitely longer than that and over in the blink of an eye, like an epic dream that you forget about seconds after waking. This dark, densely nested fairy tale about life, death and the in-between takes its cue from the writings of Polish literary great Bruno Schulz but delivers its own crumbling, freeform model of storytelling — driven less by logic than by intuitive sense and ambience, where the Quays’ signature ethereal imagery comes into play.

The opaque elusiveness of “Sanatorium” may frustrate viewers who, once sucked into the vividly tortured Gothic fantasy of the film’s storyworld, find themselves adrift in a shape-shifting narrative in which characters multiply, chronologies bend and merge, and even death is infinite. Those more familiar with the Quays’ work—particularly their influential 1986 short “Street of Crocodiles,” also freely adapted from Schulz—will be better prepared for the baroque eccentricities and inscrutabilities of their latest film, which premiered on this year’s Venice Days sidebar and is destined for extensive festival screenings, sparse arthouse distribution and a sectarian afterlife. Now in their late 70s, with celebrity champions like Christopher Nolan in their corner, the Pennsylvania-born, London-based twins still have no plans for the mainstream.

Beautifully vintage title cards announce the setting as Sanatorium Karpaty, a mysterious hospice in the foothills of the Carpathian Mountains, in 1937—the same year that Schulz published the novel with which the film shares a title, a Kafkaesque ghost and more themes than plot points. We must enter this milieu, however, through an intricate framework involving a sinister auction house. There, the detective items on the block include the fossilized ribs of a sea siren, the warm blood of bees and, crucially for the film’s interests, a “Maquette for the Grave of a Dead Retina”—a kind of shadow box animated by a sunbeam on its former owner’s preserved eye, whose seven viewing lenses lend the film its seven ornate chapter titles. (The film’s boastful language feels like its driest running joke.)