Whether half a good film is enough is the question raised by “Lion,” a true-life story in which not only do the protagonist’s first years prove far more interesting than the later ones, but the level of craftsmanship is superior in the initial hour as well. Garth Davis’ film, adapted by Luke Davies from the autobiographical book by Saroo Brierley, is designed to be a crowd-pleaser, but after a turbulent, heart-wrenching first act, the second—meant to be touchingly uplifting—instead comes across as rather shallow and pedestrian by comparison.

The initial portion of the picture recounts how Saroo (Sunny Pawar), a five-year old living in abject poverty with his loving mother (Priyanka Bose), who carries rocks to earn a meager living, insists on accompanying his older brother Guddu (Abhishek Bharate) to the train station to look for scraps of metal to sell. While Guddu goes off, Saroo falls asleep on a bench, and when he awakens his brother is nowhere to be found. The boy climbs aboard a nearby train and falls asleep again, only to be trapped when it starts up and proceeds with himself as the only passenger some 1500 miles to Calcutta.

There Saroo finds himself alone and unable to communicate (since he speaks Hindi rather than Bengali). Nearly caught up in sweeps of street children by gangs, and at one point taken in by a woman who intends to turn him over to a suspiciously considerate man, he manages to keep one step ahead of danger, but must fend for himself until a kindly young man takes him to the police. But their best efforts are understandably unable to locate the boy’s distant, illiterate family, and so he is sent to an orphanage. There he will be adopted by an Australian couple, John and Sue Brierley (David Wenham and Nicole Kidman), who whisk him off to Tasmania, where he happily assimilates—unlike Mantosh (Keshav Jadhav), the Brierley’s second Indian adoptee, whose emotional problems prove insurmountable.

This first chapter of “Lion”—which is eventually revealed as the meaning of the name he has childishly mispronounced—has a real touch of poetry to it; it might be described as an updating of the neorealist template established more than a half-century ago by De Sica, though done up with a vibrantly colored glossiness characteristic of today’s technique. Watching Saroo negotiate his way through his journey is emotionally powerful and undeniably moving, particularly because wide-eyed Pawar cuts such an engaging figure.

Then the picture moves into its second act, set twenty years later in Australia. Saroo, now played by Dev Patel, is—unlike the troubled Mantosh (Divian Ladwa)—a well-adjusted fellow who’s entered school to study hospitality management. He also meets Lucy (Rooney Mara), an American with whom he becomes romantically involved. But when some Indian friends hear his story, they suggest that he might utilize Google Earth to rediscover his biological roots. He becomes obsessed with doing so, an endeavor that causes friction with his family and Lucy both.

Grown-up Saroo’s search takes up the remainder of “Lion,” and you can be left to imagine how it ends. If one were crass he might dismiss the entire thing as an advertisement for Google Earth that doesn’t even try to be subliminal, but setting aside the promotional aspect, there’s something rather melodramatic in the way that Saroo is presented, after two decades of apparently being at best vaguely interested in his biological background, as suddenly becoming so desperate to unravel the mystery of his roots that he’s willing to treat the people who raised him and the girlfriend who’s so concerned about him with what comes uncomfortably close to disdain. Patel doesn’t help matters, emoting so broadly that he comes perilously close to tearing out his hair, silent-movie style. The result is not so much affecting as coarse, especially since Kidman and particularly Wenham underplay nicely, and Mara, while more extrovert, is working at a lower decibel than Patel as well. It could be argued that the first half of the film is no less calculated than the second, but it avoids the latter’s gratingly obvious quality, and in Pawar it has a central figure one can more easily empathize with.

So “Lion” is that not-so-rare creature, a mixed cinematic bag in which a moving set-up leads into a clumsily manipulative conclusion. It is, to be sure, elegantly appointed throughout by production designer Chris Kennedy, costumer Cappi Ireland and cinematographer Greig Fraser, who together might make the Indian sequences too beautiful considering the elements of pain and loss they represent, but certainly succeed in providing the glossiness that Davis and his producers presumably desired.

So what to do—recommend that people go to a film and stay only for its initial hour? When “Lion” comes out on DVD, that would be a practical option, so you might just want to wait until it’s available in that format.