Penetrating yet gentle, the documentary Unmistaken Child lifts the curtain on the rarely glimpsed rituals, tests, and trials of what might seem like an impossible quest to outsiders: the search for the reincarnation of a Tibetan Buddhist master.

According to Buddhist ideas of reincarnation, an enlightened teacher returns to earth after death, rather finding nirvana, or release from the cycle of rebirth, and is reborn in a new body in order to continue to help others achieve enlightenment. It’s undoubtedly a tough concept for nonbelievers to wrap their skeptical brains around, despite the Dalai Lama’s own writings on the subject and the existence of films like Bernardo Bertolucci’s 1993 feature film, Little Buddha. But there’s no mistaking the affection and intimacy established between documentarian Nati Baratz and his primary source, Tenzin Zopa, the late, renowned Tibetan Buddhist master Lama Konchong’s most devoted “heart disciple.”

After Lama Konchong passes away in 2001 at 84, Tenzin, who had been in the service of his master since the tender age of 7, is enlisted in the hunt for his new reincarnation -- a process that involves sifting through the ashes of the Lama’s remains for visual clues, divination, and the careful deployment of the late spiritual leader’s everyday possessions. The filmmaker follows Tenzin as he tearfully revisits the Lama’s now-desolate retreat, exclaims over the beauty of the “dancing” trees and flowers, cavorts happily with a blossom tucked behind his ear and reminisces about his master. And the handsome young monk becomes the sweetly charismatic -- and resonant -- center of Unmistaken Child. In many ways, Tenzin’s four-year quest -- a daunting endeavor undertaken by foot, mule, and helicopter to remote Tibetan villages tucked among incredibly beautiful mountains, which would undoubtedly frustrate the most patient soul -- is as much a search for his own very young, fresh, and playful self, as it is for his beloved late master hidden in a new infant body.

The remarkable village child -- with his preternaturally expressive glances and mysterious sense of knowing -- that Tenzin eventually discovers and delivers to the Dalai Lama is his, and our, reward, and Baratz’s perceptive and surprisingly light-hearted touch with this genuinely astonishing material will rivet Buddhists and non-Buddhists alike.

Unmistaken Child shows at Lumiere Theatre, S.F., and Shattuck Cinemas, Berkeley. For times and more information, go to landmarktheatres.com.