Zain Al Rafeea in Capernaum (Christopher Aoun/Sony Pictures Classics)

 From the start of this gritty, Golden Globe–nominated drama from Lebanon, there is a focus on just how vulnerable people can be. A young boy, Zain (Zain Al Rafeea, in real life a Syrian refugee), lives in the heart of an aggressively bustling Beirut, and he’s frequently juxtaposed in street scenes against large and noisy vehicles that look like they could crush him at any second. The opening also features a shot of a darkened room and women lined up against a wall, worried looks on their faces as an unseen voice calls out their names, although the exact reason why is unclear at first.

Making things even more complicated, the film next jumps to Zain in court, his parents on hand and looking bereaved, and a judge declaring that the boy has stabbed a man and been serving time in jail. However, the parents are the defendants: the boy is suing them. For what reason? For giving birth to him, Zain says. Director Nadine Labaki then settles into an earlier point in time to describe what kind of parents would be sued by their adolescent son.

The answer is: the kind who engage in making drugs and using their children as transports and who abuse their kids physically, which is especially true of the mother (Kawsar Al Haddad). This section of the film is full of images that are troubling, such as the sight of a baby chained to a radiator—the large family is packed together in a small, crumbling apartment. Amid squalor and poverty, Zain’s only joy is his sister Sahar (Cedra Izzam), who is about 11 and has already begun catching the eye of men on the street. When he discovers that she has had her first period, he tries to keep that information from their parents, believing they would marry Sahar off as soon as possible.

After Zain takes a job as a delivery boy to make a little extra money, he comes home to discover both his parents and another clan gathered for exactly what he feared. He and his sister make a plan to run away, but as happens over and over in the story, his timing is just a little too late. In one long, harrowing sequence, Zain screams, begs, and futilely fights his mother so that she will not send Sahar away, but she repeatedly strikes him down verbally and physically. By filming it in with a handheld camera, Labaki heightens the sense of desperation and allows the mother a chance to inflict maximum emotional damage.

In the second act, Zain has run away and, through some bizarre happenstance, ends up at an amusement park where he becomes part of a very different family from the one he left behind. He befriends a young Ethiopian woman, Rahil (Yordanos Shiferaw), who was among the detained women mentioned earlier. She works as a custodian and has two very big secrets, the first of which is that she is in the country illegally. The second: she is the single mother of a baby boy, Yonas (Boluwatife Treasure Bankole), whom she keeps in a bathroom stall and checks in on during breaks. In a wholly unexpected development, Zain agrees to stay home with the infant in exchange for shelter in Rahil’s dilapidated shed while she works.

What follows are among the film’s most moving scenes as Zain, heretofore an understandably angry young adolescent, gradually develops a tender and nurturing side—something he clearly did not get from his own parents. Playing up the sentimentality of these moments would have been a mistake on Labaki’s part. Luckily, she never loses sight of how the two characters’ living arrangement only makes their respective situations marginally better. Rahil still lives in constant fear of being caught by immigration authorities and deported with her son, an anxiety that certain parties—a human trafficker (Alaa Chouchnieh)—try to exploit. Zain, meanwhile, chafes at being trapped indoors all day and yearns to see Sahar again.

Capernaum takes an especially heavy turn when Rahil mysteriously disappears, leaving Zain to keep their makeshift household afloat however he can. He falls back on certain behaviors that will be familiar to viewers from the scenes with his parents, even if Zain doesn’t seem to recognize that he’s re-creating the past. The name of the film derives from the word meaning “chaos,” and a recurring visual motif are shots from above, in which the boy seems to be running around a labyrinth of a neighborhood with no discernible pattern. But as the narrative unfolds, it becomes clear that Zain’s life is not random at all but profoundly affected by the models he observed while growing up, flawed as they were.

This film works so well because of the terrific work by the actors, especially Al Rafeea as Zain, who is thoroughly believable as a 12-year-old desperate to control his own destiny but who finds himself consistently at the whims of fate due to his age and slight stature. Labaki reportedly based her screenplay on the experiences of her actors, who are all non-professionals, and there are times in which they do something so original that we wonder if it occurred in real life as well. For example, Zain uses a mirror to reflect a television set from the home across the street or pours sugar onto ice for a tasty treat that helps him and Yonas stave off starvation a little longer.

As previously mentioned, Labaki avoids presenting her protagonists’ situation in too sentimental a light; we never get the impression that Zain is having a good time, though he proves resourceful. There are long stretches in which the film eschews a score, giving the scenes a documentary-like feel. In addition, while Capernaum relies heavily on a baby (and a highly photogenic one to boot) as a plot device, it presents Yonas as both a blessing and a burden in equal measure. One of the biggest surprises, however, is how Labaki manages to change our perception of Zain’s parents, not necessarily redeeming them but humanizing them just enough so they are not monsters.

The film is a crowd-pleaser culminating in a courtroom scene in which Zain, who long existed out on the margins, at last gets his chance to be seen and heard. He takes full advantage of it, having earned that right. Labaki has crafted a powerful drama that calls on greater empathy, told through the eyes of someone who has lived through the harsh experiences living on society’s periphery.