This is the true story of a quest -- the quest for a song, first, and then for the woman who wrote it.

The song appears in the closing credits of "Mirror Mirror," the first of this year's two big-screen adaptations of the Snow White fairy tale. Its director, Tarsem Singh, first heard the song in the early 1970s, when he was a boy growing up in India's Punjab province.

The song was called "I Believe," and it was sung -- in English -- by a woman who might best be described as the Madonna of Iran at that time. She went by one name, Googoosh, and sported a pixie haircut presumably inspired by Mia Farrow. "As kids, we used to dance to it," Singh told The Huffington Post. "We loved it."

Three decades later, Singh played the song for his niece, who was staying with him in Montreal while he shot his 2011 film, "Immortals." "She's this clubbing girl and she loved it," he said. "Every morning when I woke up, she'd be playing it in her shower. I'd hear it in the next room. It would be Googoosh going, 'I believe, I believe, I believe in love! Love!'"

Clearly, this was a song with broad appeal -- and a special resonance for young people. So when Singh read the script for "Mirror Mirror" and decided that his film simply had to end with a musical number, it didn't take long to settle on one, he recalled: "Suddenly, I went, 'It's perfect; the movie ends with Snow White singing, 'I believe in love!'

"And then the fun started."
*****

Singh's decision set off a chain of events that spanned a year and drew in dozens of people, from studio executives to a private investigator. At the end of the trail was a woman nobody could find.

The reason for the search was simple: To include "I Believe" in "Mirror Mirror," the producers needed to secure the rights. But they had no idea who even owned those rights. "Tarsem wanted to have that song," said Bob Bowen, senior vice president of music at Relativity, which produced the film. "And then we had to figure out … how do we get it cleared? How do we license it? Who do we get to record it? And all the other production logistics that go with that."

"I just told them, 'We need this song; we need this song,'" Singh recalled. "And they couldn't get the rights. They kept saying they contacted Googoosh's people but … basically the rights belong to the Iranian government. And I said, 'That just sounds like something I don't want to believe.' I was a bit heartbroken."

Before giving up altogether, a production assistant at Relativity made a call to Koo Abuali, a former musician who had done some low-budget soundtrack work in the past and was looking for a big break. Abuali had recently moved from Los Angeles to Montreal -- where "Mirror Mirror" was being shot -- in pursuit of a love interest and, with any luck, a job on the film.

Abuali remembered getting the call on June 2, 2011: "He says, 'Um, I have a little task for you. But I honestly don't think that you're going to be able to do this.' And I said, 'If it's an opportunity, hit me with it!'"

Working with little more than the song's title and the knowledge that a woman named Googoosh had once performed it, Abuali launched a frenzied research effort. "I knew that I had a very tiny window to get in to meet with this director," she said. "And I knew that it would be an opportunity that would change my professional life."

Right away, Abuali had a stroke of luck. She tracked down Googoosh's lawyer and discovered that he was an old acquaintance from Los Angeles. But this success was followed by four days of round-the-clock frustration. She contacted the Iranian consulate, the Cannes Film Festival (where Googoosh had once performed the song) and practically everyone in the Iranian singer's circle, including her assistant, two songwriters who had worked with her in the '70s, her doctor -- and even her ex-husband, Mahmoud Ghorbani. "It was like one piece after another after another that was all adding up, but they were all leading nowhere," Abuali said.

In the end, the World Wide Web gave her the break she needed. Her Iranian friends had advised her to google transliterations of the song's English lyrics "I believe, I believe, I believe in love." Sure enough, a search for "Vabeli, vabeli, vabeli" led her to an article in Portuguese that -- when entered into Google Translate -- unlocked the mystery. The article revealed that Googoosh's "I Believe" was a cover of a song titled "Love," which had first appeared in a film called "Taking Off." It was directed by Milos Forman, the Oscar-winning director of "Amadeus" and "One Flew Over the Cuckoo's Nest," and had won the Cannes Grand Prix in 1971.

Better yet, the woman who performed "Love" in the movie was also the songwriter. Her name was Nina Hart; she was 20 years old in 1971 and an American. How hard could it be to find her?