Arthouse coming-of-age films are doing better than ever in 2017. From “Lady Bird” to “Call Me By Your Name,” festival favorites from earlier in the year are now poised for mainstream success and Oscar buzz. But the genre is a difficult one to execute, and some adolescent narratives find themselves in arrested development. Such is the case with the newest title from IFC Films and The Malloy Brothers, “The Tribes of Palos Verdes.”

The film’s narrative, adapted from the eponymous novel by Joy Nicholson, borders on trite. A nice, Midwestern family helmed by a mentally unstable mother and a philandering father moves to California for a fresh start. Their renaissance is cut short when patriarch Phil leaves the family for their real estate agent, Ava. Fraternal twins Jim and Medina, now under their mom Sandy’s volatile reign, must learn to cope. Medina uses surfing as her emotional crutch, while Jim relies on hard drugs.

‘Palos Verdes’ unfurls from sixteen-year-old Medina’s point of view. More interested in doing her own thing than fitting in, Medina is the social foil to the people-pleasing Jim. Forever bonded to him through twinhood and surfing, Medina is especially protective of her brother. “You keep my soul and I keep yours,” she explains to him in a scene, comparing them to the fictitious Morubu people. “We stick together no matter what.” As Jim gets tied up in his mom’s maelstrom of manic depression, though, Medina finds it harder and harder to stay home. She strikes up a romance with Adrian, Ava’s son, and uses him to escape for a while. But when Jim’s drug use begets irrevocable consequences, the family is left sprawling anew.

The film ultimately feels like an after-school special in indie casing. Its many conflicts are introduced flatly, with bizarre timing, leading them to make little impact. There is corny voice-over that over-explains the plot. The film moves at a stuttering pace, only occasionally upheld by its performers. Though an underutilized Alicia Silverstone breathes some much-needed life into the film as Ava, Justin Kirk and Cody Fern are forgettable as Phil and Jim. Jennifer Garner breaks her sweet facade to portray the volcanic Sandy, with mixed results. Garner’s role is 90% yelling, leaving her with little opportunity for nuance, though her manic turns are delightful and unique. Maika Monroe is disappointingly bland in the lead role, though that could be because her character is about as well-drawn as a kindergarten doodle. Monroe proved to be a very capable actor in “It Follows,” but this role refuses to let her shine.

“Surfing,” Medina answers when asked what she’s interested in. “I really like surfing a lot.” Since screenwriter Karen Croner seems to think that liking surfing is analogous to having a personality, that’s about as deep as our protagonist gets. She is untethered by any real connection to her family members — the film offers explanation as to why she and Jim are so close, other than the über-lazy “they’re twins,” and she seems equally disdainful of both her mother and father. Though she is supposed to be the film’s emotional compass, Medina offers little gradation between bawling and blank stares. Medina could be played by one of the film’s key props, a fake cantaloupe, and “Palos Verdes” would hardly change.

Early on in the film, Medina drones on about the absurd falsity of her new hometown. She defines the affluent suburb by its practiced perfection, from finely-combed beaches to thrice-painted homes. In the end, ‘Palos Verdes’ becomes the very thing its protagonist mocks. It is a film that superficially hits its mark, with a strong cast and a requisite stark indie aesthetic, but those assets merely cover up banality. The gorgeous Garner and Monroe fail to convince as women struggling against California perfection — there’s an especially absurd scene in which Garner slices her Spanx to show a flat stomach underneath. In similar fashion, there is little of interest under this film’s pristine surface. In fact, due to some smart editing, its trailer is ultimately stronger than the finished product.

“The Tribes of Palos Verdes” privileges melodrama over nuance, pitting skilled actors against a humdrum script and sketchy roles. It doesn’t offer anything new, and bungles any mildly interesting plot points. If you want to see Maika Monroe pretty-cry or Cody Fern eat puke (yes, really), you should check out this movie. Otherwise, you would probably get the same emotional payoff from a “don’t do drugs” PSA and a sunset view. [D]