Riffing on his parents' lives before he was born, Weerasethakul makes the beautiful inscrutable

Apichatpong Weerasethakul, Thailand's leading experimental filmmaker and international man of mystery, isn't exactly a master of suspense. Still, the 37-year-old director's distinctively casual cine-nigmas are anything but predictable – except, perhaps, in their unaccountable happiness.

As impervious to an easy read as its title, Syndromes and a Century – which was included in the 2006 New York Film Festival – begins with the typically Weerasethakulian image of trees swaying in the breeze. They're on the grounds of a rural hospital where, inside, the girlish Dr. Toey is interviewing a young army medic, Dr. Nohng, for a job.

Clinics are a favorite Weerasethakul location (his parents were doctors) and this one seems unusually idyllic, with tranquil sunlit corridors and group exercises outside on the grass. There's the sound of conversation as the camera zooms into an open field as a backdrop for the movie's titles – and the strange realization that, at this moment, the actors, who are mainly non-professional, are talking as themselves. This will not be the last non sequitur.

What is this movie about? Dr. Toey checks to see if a saffron-robed monk's brain is "normal." (The chatty patient describes a recent dream about angry chickens.) No less than the filmmaker, the doctor has her own way of working, interrupting the exam to run outside and ask a colleague to return some borrowed money. The monk too has his ideas; he winds up giving the doctor a potion to regulate her menstrual flow and trying to hustle a few drug prescriptions. Meanwhile, a younger monk is making his first ever visit to the dentist, explaining that his original ambition was to be a DJ or open a comic-book store. Later, dentist and monk perform a duet amid the ambient babble of voices and birds.

Syndromes and a Century, which was commissioned by the New Crowned Hope festival to commemorate the 250th anniversary of Mozart's birth, is a movie of long serene takes and gentle absurdities. Weerasethakul's style is determinedly unemphatic. Dr. Toey invites a shy admirer for lunch only to discover he's ridiculously forward. As they stroll past the statue of Buddha, he's emboldened to ask her to marry him. By way of an answer, she launches into a lengthy story about her not quite love affair with an orchid farmer- replete with flashbacks to a lunch at the very same table. Although interrupted by her admirer, Dr. Toey insists on finishing her tale-which, of course, she never does.

Weerasethakul has called Syndromes "an experiment in re-creation of my parents' lives before I was born." Like his two previous films – Blissfully Yours (2002) and Tropical Malady (2004) – Syndromes and a Century is a two-part brain tickler. The first part is set in the period of the filmmaker's childhood, the second in the present day. Midway through, Weerasethakul begins the movie again, repeating the first interview with slight differences in tone and camera placement. This time the hospital is urban, with high-rise buildings visible beyond the tended grounds. The old monk has a different doctor and another diagnosis-namely, panic disorder.

The camera has more glide here and the central anecdote less traction. After his interview with Dr. Toey, Dr. Nohng wanders through the hospital into a workshop for the production and fitting of prosthetic limbs. Two middle-aged lady doctors invite him for an afternoon drink from a bottle of liquor stored in an unused false leg. Out in the corridor, a disturbed teenager is swatting a tennis ball and talking about his past life. Dr. Toey is around but Dr. Nohng isn't very interested. He has another, more glamorous, girlfriend who shows him pictures of her company's new plant and suggests that he relocate there with her. Nothing much happens. Dr. Toey sits at her desk and stares. The hospital workshop fills up with mist. Lunchtime aerobics are staged to an inanely cheerful beat-is this the modern Mozart?

Syndromes and a Century presents a world in which multiple times coexist and more-or-less congruent personalities experience two different sets of lives, working in two different hospitals. Are these parallel tales a Buddhist romance? An attempt to induce something like 3-D narrative depth? A consideration of repetitive human activity over the course of a lifetime? You might as well ask why the breeze is rustling the leaves.