“Wendy,” the new film from Benh Zeitlin, opens with tender caresses and shimmers of radiant light. Much as at the start of his smashing feature debut, “Beasts of the Southern Wild,” the camera is trained on a young girl whose world is filled with wonder, strange rituals and phantasmagoric shocks. In “Beasts,” the girl was called Hushpuppy and she lived in a tumbledown paradise called the Bathtub. Here, the girl is Wendy and she lives in her own ramshackle utopia, one that borrows a little from “Beasts” and, more generously and unproductively, from J.M. Barrie’s “Peter Pan.”

There are other similarities between Zeitlin’s two films, including sumptuous cinematography and a rousingly propulsive score, a rabble of charming children and nods at our environmental crisis. With its exquisite, near-cubistic close-ups of a toddler in a woman’s arms, the opener of “Wendy” suggests that Zeitlin has embraced abstraction even more boldly than he did in “Beasts.” Here, the child, a cherub with a halo of dark curls, comes into focus gradually. Like the pieces of an unsolved jigsaw puzzle, she appears in fragments — a downy arm, a prettily lashed eye, a face outlined by honeyed light — that sweetly suggest she’s very much a work in progress.

It’s a lovely start and for the next 50 minutes or so Zeitlin keeps adding more beauty, filling in the background and adding detail as the film pleasantly drifts. Even when Wendy grows older, becoming a rather sober 9-year-old (Devin France), the whole thing meanders, swirling rather than marching forward. Then one night Wendy and her brothers hop a train, coaxed aboard by a laughing boy called Peter (Yashua Mack), and the drift gives way to churn, to chugging wheels, driving music and skin-prickling momentum. Wendy is clearly off on an adventure, ready to take flight. But when the children arrive on a lush volcanic island, the film stops dead in its tracks.