Without any doubt “Secondhand Lions” is a manipulative movie, just as Tim McCanlies’ earlier effort, “Dancer, Texas Pop. 81” (1998) was. While that picture painted a nostalgic portrait of four young men coming of age in a tiny Texas town, however, this one focuses on the loving relationship that develops between a boy abandoned by his flighty mother and the irascible, elderly grand-uncles with whom she leaves him. (The time is the memory-drenched 1960s.) Much of what occurs is ostentatiously quirky, and the sentimentality quotient goes off the charts. But when you have Robert Duvall, Michael Caine, and Haley Joel Osment in the leads, does all that really matter? Nope. The picture works like a Disney live-action film of the 1950s–one of the classic ones. It’s a crowd-pleaser of the most old-fashioned sort, and who cares about calculation when it’s served up with so abundant a desire to please and blessed with a cast like this one?

Osment plays Walter, a sad-faced fourteen-year old whose single mom Mae (Kyra Sedgwick) drops him off at the isolated farm of grand-uncles Garth (Caine) and Hub (Duvall), ostensibly so that she can go off to Fort Worth to study cosmetology. The two old men are gloriously cantankerous old coots, taking sport in running off traveling salesmen with their rifles and literally shooting fish for supper, and they deposit the kid in a tower room of their spooky ramshackle house. Gradually, however, the boy and the old men begin to connect, and Walter begins to search for the secret of their mysterious past, not because his mother had told him that they’re rumored to have millions stashed away somewhere (a notion corroborated by the periodic appearance of a family of sneaky, obviously greedy relatives), but because he becomes fascinated with finding out why Hub regularly sleepwalks toward a nearby pond to engage in mock battles with an unseen foe. The answer comes–perhaps–in some Arabian Nights-like tales that Garth tells the boy about the brothers’ adventures in Africa–stories that involve the Foreign Legion, a beautiful princess, a jealous sheik, lots of swashbuckling, and a great horde of treasure. Whether the stories are true or fiction is doubtful, of course, but they seem confirmed by Hub’s ability to toss aside a gang of young hooligans all by himself.

There’s a strong dose of the hokey in all this, of course, and McCanlies’ script is just a series of well-judged routines (like Hub’s thrashing of the youngsters) designed to charm the socks off us and elicit an occasional sniffle. There’s an episode involving a vegetable garden, for instance, that uses a set of brand-new store-bought overalls as props, and depends for its punchline on seeds purchased from a deceptive salesman. There’s the subplot that lends the picture its title, in which Garth and Hub purchase a lion with the intention of hunting it for sport, only to find that it’s as decrepit and lovable as they are (it becomes Walter’s pet, and proves itself as protective of him as they are when Mae returns with a man who aims to find the old fellows’ purported pile of loot). There are even periodic appearances by a herd of animals–a pack of personable dogs and a Babe-like pig that apparently thinks it’s a canine, too–that practically scream out “Aren’t they cute?” (It’s precisely the same rhetorical question that the script poses every time Garth and Hub engage in some new eccentricity.) And then there are the warm, sentimental patches–when one of the oldsters falls ill, when gruff Hub and Walter finally embrace, and the denouement, when Mae comes back to reclaim her boy and he’s reluctant to depart. It could easily be argued that McCanlies piles it on very deep by adding an epilogue in which the truth about the men’s past is posthumously revealed.

But it would take a curmudgeon even more dedicated than Hub to scowl at “Secondhand Lions” and mean it. Like his three heroes, McCanlies is adept at planting corn, and in this case it proves a succulent crop. His good-natured script is one reason for this, but his skill in assembling the leads is even more important. Duvall is masterful–he could probably play this crotchety guy in his sleep, but he seems really engaged by it, and when he turns soft it’s genuinely touching. (Together with his recent turn in “Open Range,” it reminds us of how his mere presence on screen now unleashes a flood of audience affection.) The more gentle, genial Caine is a joy to watch too, even if his accent does occasionally wander. And Osment keeps pace with them; he’s not the little boy of “The Sixth Sense” anymore, but he’s still a scene-stealer. (He tweaks his voice up an octave for “cute” effect too often, but carries off the big emotional moments beautifully.) This is basically a three-hander, but Christian Kane and Kevin Michael Haberer exhibit considerable panache as the younger versions of Hub and Garth in the fantasy flashbacks (Emmanuelle Vaugier is no slouch as the princess, either); back in the sixties, Sedgwick and Nicky Katt are capable as Mae and her newest beau, and Michael O’Neill is suitably slimy as the grasping relative. Josh Lucas shows up in the epilogue as a cartoonist with a special interest in the grumpy old men.

“Secondhand Lions” was shot near Austin, and though modestly budgeted, it makes good use of the locations. Jack N. Green’s cinematography is nice, and the period detail well caught in David J. Bomba’s production design–which also gives the “African” sequences a chintzy charm. Patrick Doyle’s score can get a bit too insistent at times, though. When a dessert is this rich it doesn’t need another helping of sugar.

So while “Secondhand Lions” may not honestly earn every smile and tear, and at times the level of treacle threatens to become a flood, it’s so skillfully manufactured that you probably won’t mind.