A clip from "Black Angel" by Roger Christian.

For decades it was a missing relic of the "Star Wars" era: an Arthurian tale about a knight returning from the crusades who is transported to a mystical realm where he must rescue a princess.

Called "Black Angel," the 25-minute movie was written, directed and produced in 1979 by Roger Christian, an art director who won an Academy Award for his set decoration work on "Star Wars."

"Black Angel," which was made with the support of "Star Wars" director George Lucas, was screened in Europe and Australia as a short film just before showings of "The Empire Strikes Back" in 1980.

It was never screened again.

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Until recently, Christian had assumed the original film prints were lost. Now, thanks to a serendipitous discovery by an archivist at Universal Pictures and services volunteered by Emeryville, Calif., visual effects company Athena Studios, the movie has come back to life.

This week a digital restoration of the movie made its North American theatrical premiere at the 36th annual Mill Valley Film Festival in Marin County. Christian plans to release the film on Netflix and Apple's iTunes early next year.

"I've waited three decades to be able to show this film to audiences once again," Christian said. "I'm so grateful."

The London native, now 69, had just finished work on Ridley Scott's "Alien" and Monty Python's "Life of Brian" when he decided to take the leap from decorating and designing film sets to directing his first feature.

He saw his opportunity when he learned that Lucas was dissatisfied with the short film that had accompanied the original "Star Wars" in Britain. For "The Empire Strikes Back," Lucas wanted a film that was more compatible with his movies' themes.

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Christian had gone back to school to study film direction. While a student at the National Film School near London, he wrote a script for "Black Angel," a romantic tale that, like Star Wars, was influenced by legendary Japanese filmmaker Akira Kurosawa.

Lucas liked the script and instructed executives at 20th Century Fox to let Christian make the movie with the help of a British government grant worth about $50,000.

"George said, 'Go and make it,'" Christian said.

Traveling in a Volkswagen camper bus and towing a horse trailer, Christian took a crew of 13 people to the rugged western Highlands of Scotland, where they filmed at Eilean Donan castle. They used a local school pool to film an underwater scene, and shot the entire movie in just seven days.

To save money, Christian used leftover rolls of film from "The Empire Strikes Back." He also relied on makeshift practical effects, including a spray can for simulating cobwebs. He used slow motion in some battle scenes to make the film longer.

The movie was released in 1980 with screenings of "The Empire Strikes Back" in Britain, some other European countries and Australia.

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"Black Angel," however, was never shown in North America, where theaters at that time were no longer screening short films before major features, unlike their counterparts in Europe.

Nonetheless, the film's style and look influenced several other fantasy films, including the 1981 film "Excalibur."