The title “A Normal Family” gives a fair indication of what a new South Korean movie is about and how its story will be told. Exploring a dysfunctional extended family, the film is a bluntly ironic drama. 

This description tells only a part of the story, though, for it fails to address some of the movie’s other elements, like its social observations, while also ignoring how its name might be a sincere comment on how most families are fractured and thereby “normal.” It’s as if the film is suggesting an elaboration of Leo Tolstoy’s popular saying, something along the lines of “each unhappy family is unhappy in its own way, yet taken as a whole, constitute a higher percentage than happy families.”

The family at the center of the film consists of brothers Jae-wan, a criminal defense lawyer with a young wife and a new baby, and Jae-gyu, a principled pediatrician married to Yeon-kyung and within whose home their elderly mother resides. Both siblings also have teenagers in their households: Hye-yoon is Jae-wan’s daughter, whose mother died and who isn’t close with her stepmother Ji-su, while Si-ho is the meek, bullied son of Jae-gyu and Yeon-kyung. 

The film’s plot concerns these two cousins, specifically an act of brutality they commit, yet director Hur Jin-ho isn’t as interested in them as he is in their parents and how they process their children’s behavior. As with many South Korean movies, violence is a recurring motif and social honor a major theme.

Despite the seemingly tailor-made story, the movie is actually based on “The Dinner,” the 2009 best-seller written by a Dutch author, Herman Koch. Mr. Hur’s version is the fourth adaptation of the book, with previous films hailing from Holland, Italy, and the U.S. How parents deal with disaffected, troubled teens is, of course, a worldwide, ever-relevant issue, as evidenced by a recent Netflix hit series, “Adolescence,” which focuses on an English family reeling from the accusation that its youngest member murdered a young girl.

Mr. Hur made significant changes to the source material, not only veering from the book’s structure but updating it to the age of social media. A tragic incidence of road rage that soon goes viral opens the film, while glimpses of both families at their breakfast tables, with each father and his respective teenage child on their phones, suggest a breakdown in communication and parenting.

Rather than a single dinner, the filmmakers have the two brothers and their wives meet for dinner regularly over the course of the film, sometimes in a high-end restaurant and once in Jae-wan’s luxury apartment. The brothers are nothing alike; the respectable-looking older brother, Jae-wan (Sul Kyung-gu), is quietly wily and pragmatic, while Jae-gyu (Jang Dong-gun) exhibits traits normally associated with doctors, such as caring and consideration. These personalities come off as too obviously incompatible, with their exchanges feeling perfunctory and mock-melodramatic, and the same applies to how the middle-aged Yeon-kyung (Kim Hee-ae) clashes with the younger Ji-su (Claudia Kim).

Their initial dinner discussion addresses whether the brothers should place their mother in a care facility, an issue important to many middle-aged offspring. After grainy footage of Hye-yoon and Si-ho assaulting a homeless man comes out online, the moral dilemma regarding generational responsibility and accountability deepens during the next meet-ups, with the already tense relationship between the brothers becoming more strained as Jae-gyu wishes for the cousins to turn themselves in. This wish also creates friction with his wife, who wants to protect her son. Later, she attempts to absolve the boy’s actions by bringing up to her husband the volunteer work they’ve done.

The hypocrisy of “do-gooders” provides the film with its most trenchant exploration, reflected in how during the first half Jae-gyu and Yeon-kyung are the more likable duo, but by the end Jae-wan and Ji-su seem the wiser and more human. All the adult actors are effective in navigating their characters’ shifting stances, though Kim Hee-ae must bear most of the weight of certain scenes’ dramatics and strenuously ironical pronouncements such as: “If kids turned out like parents intended, why’d anyone go to church?”

Actress Hong Ye-ji plays Hye-yoon as a typical callous teenager, though her unremitting insensitivity makes her out to be less sympathetic than some silver screen serial killers. Kim Jung-chul’s portrayal of Si-ho highlights the character’s impressionability and tender immaturity, particularly during a late scene with his father. Yet the two remain inscrutable, and the film continues its focus on the parents all the way to its violent end.

Stylishly directed though slackly edited, “A Normal Family” contains some well-observed moments but ultimately isn’t a nuanced look at parents and progeny. Mr. Hur has orchestrated an overwrought tale of brotherly rivalry that makes overtures to seriousness and contemporary critique, yet its major chords are genre notes, sensationalist, and easily cynical.