There are two things that will stick with viewers who see Andrew Neel’s adaptation of Brad Land’s 2004 memoir about hazing at a college fraternity. One is the recreation of the hazing itself, which is done so realistically that the scenes of humiliation and punishment are not just harrowing but physically difficult to watch. The other is the acting of Ben Schnetzer as a freshman pledge who suffers the treatment, and Nick Jonas as his older brother, who’s already a member of the frat but grows disgusted watching his sibling endure the ritual that he presumably underwent himself.

The plot itself, however, offers relatively few surprises, and writer-director Andrew Neel (along with co-scripters David Gordon Green and Mike Roberts) don’t manage to clarify some of the major characters’ motivations as fully as they might. After high-school senior Brad (Schnetzer) is brutally assaulted when he unwisely gives a ride to two unsavory guys after leaving a party at the fraternity where his brother Brett (Jonas) is a member, his recuperation is a long one, and he doubts the wisdom of going to college at all; but ultimately he relents, and not only enrolls at the same college Brett attends, but decides to pledge at his fraternity as well, accompanied by his somewhat wussy roommate Will (Danny Flaherty).

The treatment they and the other potential frat brothers receive at the hands of the year’s sadistic chapter heads, president Chance (Gus Halper) and pledge master Dixon (Jake Picking), is presented with a grim realism that makes it all the more repulsive. Indeed, the film luxuriates in the mindless cruelty to the extent that you might begin to suspect that the makers either find it too fascinating to abbreviate, or believe that viewers will want an extended experience of it. (Certainly the cinematography by Ethan Palmer, which gives the hazing sequences a degree of glossiness at odds with their ugly content, pushes that idea.) But one can assume that all the nastiness is meant to make the ritual so grotesque that it will cause you to wonder about a mid-set that enjoys inflicting such punishment; that purpose is also behind an intrusive cameo by James Franco, who appears briefly as a gung-ho alum brother to emphasize the ridiculously macho character of the camaraderie of Phi Sigma Mu.

The turn that the narrative takes in the end, however, is a pat one, no more unexpected than the one that some might recall from the little-seen “Fraternity Row” of 1977. That the frat will come under scrutiny due to a tragedy is almost a foregone conclusion, and that Chance and Dixon will find themselves in the crosshairs is equally certain. That part of the plot, unhappily, is undercut by the overdrawn turns of both Halper and Picking, neither of whom manages to avoid caricature. Nor does Flaherty, whose turn as a campus doormat never goes beyond the obvious.

Far more interesting is the relationship between Brad and Brett, especially since Schnetzer and Jonas inhabit the roles so successfully. Schnetzer, who played the scraggly CIA analyst opposite Joseph Gordon-Levitt in “Snowden,” brings a full range of emotion to the younger brother. It’s true that his rationale for trying to join the fraternity that had been at least partially responsible for what befell him earlier is never spelled out; one has to intuit that it has something to do with his desire to prove his manhood after the beating he’d taken. But though one might wish for more clarity on that score Schnetzer plays the conflicted young man skillfully.

Meanwhile Jonas, who was so wooden in the recent “Careful What You Wish For,” shows marked improvement here. He can still be a trifle stiff, but while the script, again, fails to make explicit why Brett turns against the entire hazing process so abruptly (or why his brothers don’t take him to task for doing so), he manages to quietly convey the anger roiling beneath the character’s surface. It seems that Jonas’ stint on the cable series “Kingdom” is proving a good training ground for him in more ways than one.

This is, it should be clear by now, a movie about young males, and though there’s an early subplot about Brad’s interest in a girl (Virginia Gardner), it’s dropped pretty quickly.

Movies generally treat frat life as something of a male rite of passage that’s outrageous but goofily harmless—thus the string of comedies that range from “Animal House” to “Neighbors.” But as depressingly frequent news stories make clear, there is a very dark side to the fraternity mindset, and despite its flaws “Goat” at least offers a glimpse of it. Ultimately, though, it’s the story of the real brothers, well played by Schnetzer and Jonas, rather than the pseudo ones of the frat that gives the picture its power.