The chilling drama “Perfect Sense” struck me as one of those super-colossal mega-bummers in the vein of “Children of Men” and “Blindness” (containing scenes shot on four continents, it may also remind some of “Babel”). Yet the film has a payoff, a big one that made me completely change my mind about what it was doing. It winds up being a formidable work of art, an emotionally devastating piece that approaches large questions in a completely unexpected way. I liked it better than “Children of Men,” a movie that struck me as being part of an ashy string of apocalypse films (“The Road” and “Wall-E” are others) meant to appeal principally to a self-hating element of today’s US-European audience that seems to feel a hard rain is not only gonna fall, but probably ought to, given our wicked ways.

“Perfect Sense” is set in Glasgow, where a somewhat cold-hearted chef (Ewan McGregor), who in the opening minutes is seen ordering a woman he has just picked up and had sex with to leave his bed before morning, strikes up a flirtation with an epidemiologist (Eva Green). She, Susan, is studying a curious case that grows into a worldwide pandemic: Victims first suffer a brief bout of immense grief that makes them sob uncontrollably about all of the wrongs they have done, then robs them of their sense of smell.

I can’t reveal more about the plot by screenwriter Kim Fupz Aaekeson, who has excellent reasons for focusing on a chef and an epidemiologist. But, as fierce and brutal as director David Mackenzie’s vision is, he knows exactly what he is doing. This is the first movie of the festival that made me cry. And not only that, I had to sit in the dark for five minutes after the movie ended to try to pull myself together.