A coming-of-age story with a strong afterschool-special vibe, “All Summers End” (previously titled “Grass Stains”) rises above the usual standards of such fare by reason of outstanding contributions from the cast, both the youngsters and the adults. While Kyle Wilamowski’s debut feature, which has obviously been sitting on the shelf for awhile—it was shot in 2013, and both Tye Sheridan (“Ready Player One”) and Austin Abrams (“Brad’s Status”) look very young indeed—can’t entirely transcend its didactic roots, the performances make it reasonably watchable.

Set in a small North Carolina town around the close of the twentieth century, the plot hinges on Conrad Stevens (Sheridan), a sensitive sixteen-year old who spends most of his time hanging out with his long-time pals Hunter (Abrams), an aggressive hothead, and Tim (Ryan Lee), a submissive sidekick type somewhat reminiscent, given his prominent front teeth, of John Megna’s Dill from “To Kill a Mockingbird”—partly as a way of escaping the stifling attention of his mother (Paula Malcolmson), whose husband has abandoned them. Conrad’s puppy dog interest in neighbor Grace Turner (Kaitlyn Dever) is rewarded with a like response from her, but the scorn of Hunter and Tim over his lovey-dovey attitude embarrasses him.

To get back on his buddies’ good side, Conrad ditches Grace for a fireworks celebration and instead goes joyriding with them, and to prove himself he attempts a prank at the Turner home that goes tragically wrong, ending in the death of Grace’s brother Eric (Beau Mirchoff).

Filled with remorse, Conrad tries to comfort Grace, and she responds to him romantically. They begin spending all their free time together and even getting intimate—something that concerns his mother, and disturbs her parents (Annabeth Gish and Bill Sage), who had initially welcomed Conrad into their home but feel very differently about him after stumbling on evidence that he had spent the night with their daughter. Both youngsters try to resist their parents’ demands that they stop seeing each other, but inevitably the truth about Eric’s death will emerge.

The major strength of “All Summers End” is Sheridan’s performance, which mirrors the excellent work he did in such early films as “Mud” and “Joe.” He actually gets to act—something that blockbusters like the “X-Men” films and “Player One” don’t really allow for—and responds to the challenge with considerable nuance and pathos. Abrams and Lee do good work as well, as a heel and a frightened doormat; each even manages his inevitable mini-redemption scene fairly well. Malcolmson, Gish and Sage also contribute skillful turns as parents who aren’t quite as clueless as those in stories like this usually are.

Dever offers a first-rate turn as well, but Wilamowski’s script is less successful in fleshing out Grace than it is with Conrad. Despite suggestions that she harbors a rebellious streak and a brief reference to the fact that she feels some guilt over Eric’s death too, the character’s motivations remain opaque, and that flaw is a nagging failing in the movie. So is another miscalculation Wilamowski perpetrates: using a wraparound flash-forward to an older Conrad (Pablo Schreiber), interacting with his own young son as the boy experiences a first crush and offering bromides and life lessons to us about what he learned from his brief time with the Turners. His words have all the subtlety of a jackhammer on concrete, and Schreiber’s delivery of them sounds like a voice from above declaring truths that, thanks to the efforts of the actors, have already been effectively dramatized.

The production values here are modest, but Wyatt Garfield’s camerawork gives the images a properly raw appearance. Julian Robinson and Michael P. Shawver’s editing, however, sometimes goes slack, though the languid pace does allow Sheridan and Dever to add shading to their characters.

It’s easy to see why “All Summers End” had to wait so long for even limited distribution. It’s not merely a small film, but one with significant script problems, including a tendency to sermonize. It does, however, offer the opportunity to watch some fine young actors do excellent work.