The abundant charm of first-time actor James Rolleston, playing the 11-year-old of the title, doesn’t quite save this aimless, nostalgia-woozy second feature from Taika Waititi (after his 2007 Eagle vs. Shark). Set in 1984 in a Maori community in eastern New Zealand, the film is dominated by Michael Jackson’s Thriller: Boy pathetically moonwalks to impress a crush, and imagines, in two of several fantasy sequences, his deadbeat yet idolized dad, Alamein (Waititi), playing the King of Pop in the “Beat It” and “Billie Jean” videos. References to E.T., Musical Youth, and Shogun also turn up, but these pop-culture signifiers aren’t enough to make up for the lack of a plot (or even a purpose). Boy works best when focusing on its pre-adolescent protagonist and his 6-year-old brother, Rocky (Te Aho Aho Eketone-Whitu, another impressive newcomer), motherless children prone to magical thinking yet burdened with too much responsibility. Troubles arise when anyone taller than five feet is onscreen, particularly Waititi, who quickly becomes his film’s biggest liability. Enervating, repetitive scenes of Alamein’s unhinged behavior (raging, bullying, drugging, digging for buried treasure) suggest the writer/director/actor underestimated the talents of the little shavers he assembled—or was unwilling to relinquish to them more screen time.