Joining a long line of filmmakers who’ve fictionalized their comings-of-age in one regional punk scene or another, veteran New Zealand writer-director Jonathan Ogilvie turns the clock back to 1979 Christchurch in “Head South.” Its protagonist is the classic shy but would-be rebellious teen boy dared into starting his own band, whose first gig naturally provides an underdogs-triumphant climax. Pleasant but awfully thin, feeling like a short insufficiently fleshed out to feature length, this modest nostalgic exercise provides a lightweight opener to this year’s Rotterdam fest. 

Angus (Ed Oxenbould) is a high-schooler intrigued by new U.K. sounds as yet little-heard hereabouts —though he can barely summon the courage to enter Middle Earth Records, where proprietor Fraser (Jackson Bliss) is the obvious go-to source for such breaking intel. Even more intimidatingly cool is mysterious Holly (Roxie Mohebbi), a Debbie Harry-esque bottle-blonde bombshell who claims to be from London. Amongst his own, younger age group, Angus has just succeeded in alienating best mates Jamie (Trendall Pulini) and Stuart (Oscar Phillips) by selling them oregano masquerading as pot. 

On the home front, things are equally unsettled: Our hero comes home one day to find his mother has inexplicably vacated the premises for a two-week motel stay, leaving behind a cryptic note and a fortnight’s worth of precooked dinners. This leaves him with dad Gordon (Marton Csokas), a civil engineer whose staid qualities and drinking habits presumably drove her away. It’s an uneasy atmosphere brightened when Angus’ older brother, at college in England, mails a care package including the first single by Public Image Ltd. — John Lydon aka Johnny Rotten’s post-Sex Pistols band. When Angus hears it (the still-exhilarating “Public Image”), the impact is such that the screen image goes from Academy ratio to wide. 

Surprisingly, though, “Head South” has few such moments that channel the dynamism of punk music or the combustive energy of its early fans. It’s mostly a soft seriocomedy with tepid humor and underdeveloped conflicts. Even after he cuts his shaggy hair to spiky brevity, then gets encouraged (by Fraser) and bullied (by Demos Murphy’s note-perfect local Rotten poseur Malcolm) into starting a band with knowing chemist-shop clerk Kirsten (Stella Bennett), Angus remains a wide-eyed naif. We never gain much insight into his parents’ marital woes, or Holly’s murky travails with surly Andy (Arlo Gibson), who might be her pusher or pimp. 

When the fadeout abruptly brings tragedy into this picture — a turn torn from real-life experience, as evidenced by closing dedication text — its force is muffled by the fact that the film has done almost nothing prior to mine character depths or stir our own deeper emotions. What ought to play as a sobering slap in the face after a wild ride instead comes off as an incongruous tonal shift interrupting exceedingly restrained hijinks. 

Which is not to say “Head South” (whose title song, as well as another played by Angus’ band, was written by the director himself) isn’t enjoyable within its limitations. Most of the performances are expert, even if we wait in vain for the script to give them more to chew on. Csokas fares best with the thin material, lending Gordon a sly edge that suggests he’s got more dimensions than he or the movie care to reveal. There’s some good music heard, if not as much as one might expect — particularly given that the original score is from Shayne Carter of the great late-’80s/early-’90s New Zealand post-punk band Straitjacket Fits. 

Ogilvie actually made music videos for acts on that outfit’s influential label Flying Nun Records in the 1980s. He applies various retro techniques to make the film look like an artefact from back then, including jump cuts, fisheye lenses, light flares, signs of faux film-stock distress, and so on. But these quasi-rough stylistic tropes tend to underline what the feature never quite achieves: approximation of the messy exuberance that made punk attractive in the first place. It’s a strangely mild-mannered, small-caps tribute to a movement that was more inclined to loudly (as a Bible-borrowed 1986 Nick Cave album title put it) kick against the pricks.