Director Azazel Jacobs’ “Terri” is a coming-of-age story, but not quite the one you might expect.

There’s not much of a narrative arc as the film simply details the day-to-day existence of the overweight, downright odd Terri (Jacob Wysocki). Terri wears pajamas to school every day and rarely utters a word until Vice Principal Fitzgerald (John C. Reilly) takes him under his wing. From here, the film takes off, integrating Terri into a loose social circle of so-called friends and alternating between sequences that are deeply humiliating and emphatically humanizing.

Wysocki carries the film on his shoulders, managing to avoid the uneven acting that can derail coming-of-age stories with his quiet, assured performance. His performance is utterly devoid of fear or self-consciousness, even when Terri is wracked with both. Reilly also impresses as Fitzgerald, whose constantly shifting motivations and attitude keep the audience guessing, even as his charming, genuine performance in making friends with Terri feel organic and sweet.

However, Reilly is off-screen for the film’s most memorable scene — a lengthy evening Terri and two friends spend drinking in the shed behind his house. It’s the film’s centerpiece, and performers Wysocki, Olivia Crocicchia, and Bridger Zadina step up to unravel an ambitious, suspenseful and often hilarious sequence as the evening twists and turns.

While the narrative falls short of satisfying, there’s still too much to like in the film to discount it entirely. From Wysocki and Reilly’s easy, funny interplay to the squirm-worthy shed scene, “Terri” is a major departure from the traditional coming-of-age film even as it manages to work in many of the cornerstones of the genre in subtle, effective ways.