Kidnapping is a common parental nightmare in a tabloid-saturated age, but only a diabolical mind, or a dizzy screenwriter, could cook up the bizarre fate of Japanese schoolgirl Megumi Yokota. Snatched from a street corner in 1977, the 13-year-old was at first considered a run-of-the-mill missing person by police. Twenty years later, as “Abduction: The Megumi Yokota Story” explains, clues emerged, and things got weird: The culprit was a North Korean spy.

This suspenseful but flawed documentary, which opens today at Village East Cinemas, centers on Megumi’s parents and their painful attempts to root out the barest facts about her disappearance. Mr. and Mrs. Yokota, who are the picture of devotion, endure cautious diplomacy by the Japanese government, flamboyant duplicity from the North Koreans, and unresolved grief.

The unfolding of the tragedy proved an emotional free-fall for the parents. First, clues from a journalist and a North Korean defector offered the shocking possibility that their daughter might actually be alive. Ultimately, North Korea admits to abducting not one but 13 people, but also offers alleged proof of Megumi’s death. The first high-level Japanese visit to the “hermit kingdom” occurred only in 2002, after years of tearful, angry protests by the Yokotas and other families about the so-called abduction issue.

The filmmakers, Patty Kim and Chris Sheridan, put a human face on hapless victims of North Korea’s warped actions. Often what little we know of the country can seem merely outlandish or even comical, like its leader’s levitating hairdo or the totalitarian kitsch of its propaganda tirades and mass gymnastics demos. The film’s account of Megumi’s 40-hour transport in a dank shoebox hull and virtual enslavement renders the country’s unmitigated horrors vivid and personal.

At times, an imposed backbeat of true-crime-style suspense undermines the film. Megumi’s mother remarks that their saga feels like being in a movie, and the filmmakers perhaps took her too much at her word. For as long as possible, we are strung along as to Megumi’s fate. The pacing and a few flashes of re-enactment clash with the compassion otherwise shown for the suffering parents. At one point, a caption about Megumi’s cause of death is withheld for a beat for effect.

The hard sell is doubly unnecessary because the family’s anguish and North Korea’s audacity are already riveting. Mr. and Mrs. Yokota, though a tight knit couple, undergo a screen-ready split over the spiritual ramifications of the event: She finds solace in God’s mysterious ways; he can’t believe a fair God would have abandoned Megumi. The North Korean defector, a wan ex-spy, testifies that killing people is as easy as killing animals, but also admits shame about this indiscriminate kidnapping by a former colleague.

Most astonishing is North Korea’s reported reason for the kidnapping, which suggests that Kim Jong Il bases his villainous statecraft on comic books. Megumi and her fellow victims were intended as model Japanese to teach his spies how to walk and talk like Tokyo or Osaka natives. Here is a level of impunity that’s hard to imagine, an international outrage that resonates with the family tragedy.

In filling in some political context, “Abduction” surpasses another BBC-affiliated documentary about North Korea. “A State of Mind,” a landmark of access released in 2005, chronicled the training of two girl gymnasts for a mass performance but failed to place the human interest story in perspective. “Abduction” goes a little further, though not far enough, by showing the challenges facing Japanese leaders as they balance the abductions against North Korea’s nuclear threat and need for famine relief.

Unevenly wrought, “Abduction” isn’t pretty to look at nor particularly insightful, and it frequently loses its footing when expanding to cover other abductees. But the Yokotas’ persistence, which essentially required assuming every North Korean claim to be a lie, is a moving mix of emotional and civic heroism in extraordinary circumstances.