Dooman River opens so slowly that for a long time I thought my DVD player was frozen. On an ice-covered river, two people make a long, slow approach. Finally, they look down, and the camera pulls back to reveal a child’s prone body. “Chang-ho?” say the adults. The figure jumps up and runs away.

Why has the child been playing dead on the ice? Is it a game or a wise subterfuge? To Chang-ho and his friends in this northern Chinese village, the river is part of their larger playground. It’s desolate and beautiful. It’s also, however, the forbidding border with North Korea.

Like all children everywhere, these kids explore and seek to understand their surroundings. They hang out in an abandoned warehouse and often run across the frozen river, hoping to sneak past border patrols. Chang-ho befriends a boy from the other side. When he invites him home to eat a meal with his sister, who is mute, the child attacks his food ravenously. He’s a formidable soccer player and shares an interest in stamp collecting.

Dooman River unfolds delicately. Director Lu Zhang is almost painterly in his approach. He loves long shots and constructs intricate frames from windows and doors. It’s more like a slideshow than a movie, an unhurried series of clues and puzzles.

In this stark film, the snowy, majestic landscape is more a character than the actors. It dwarfs them. Lu Zhang reveals a unique place where the boundary between the remote Chinese village and the mysterious, oppressive North Korean regime is both porous and dangerous. The border is a testing ground for the kids, who naturally try to see how much they can get away with. But adults warn they shouldn’t know too much about what’s going on across the river. Are people really starving? Should the refugees who make daring escapes be welcomed or feared?

Dooman River uses the perspective of young people to sort out the inexplicable issues adults have raised by dividing a gorgeous natural world into separate territories full of menace and dread. In this place, coming of age is learning the border river’s rules and the punishments for defying them.

Because of Lu Zhang’s habit of distancing his camera from his characters and parceling out the plot in sparse, barely connected bits, the tension builds imperceptibly. It seems for long stretches that nothing much is going on, but that’s an illusion like the river itself–a deadly serious reality hiding in plain sight.

The sudden shock of the powerful climax to the film creeps in on quiet footsteps then dissolves in a stunning dreamlike allegory. It turns out that bridging the river is nothing but a dream of the past, like the innocence of childhood itself. Despite its slow pace, Dooman River will richly reward the attention of a patient viewer. The Michigan Theater screens it October 5 as part of the U-M’s Nam Center for Korean Studies’ latest film series.