Tom Letness has always loved German cinema. The artistry, the melancholy. And he's long been fascinated by films from beyond the Iron Curtain, collecting movies and recordings from East Germany.

But until he saw the documentary "East Side Story," the Heights Theater owner had missed a major subgenre: Communist musicals.

"That was something I had no idea even existed," Letness said. He remembers thinking: "Wow, this is a door that's opened up."

The film aficionado dug in, unearthing a DVD of a film briefly shown in the documentary — "Heisser Sommer," or "Hot Summer." He fell for the 1968 film, which follows teenage friends on a rollicking road trip, and vowed to show it at his Columbia Heights cinema.

But good-quality, big-screen versions of the film are extremely rare. So finding one became tricky.

The resulting June 14 screening is part of a "Rock 'n' Roll Is Here to Stay" series, put on by the Heights and Trylon Cinema. Letness, 56, dreamed up the series, he admitted, mostly to show this one musical. "I thought, 'God, I'd really love to show this movie,' " he said. "How can I do it and justify it?"

"Hot Summer" is a beach musical, decades later touted as "The East German Grease." Two groups of carefree teenagers hitchhike to an island on the Baltic Sea. At first, the group of female friends rebuke the guys. But after their paths keep crossing, romance blooms. "If you were to watch it, and you weren't paying attention, it looks just like any Western musical," Letness said, with lively choreography and fetching stars. The movie's leads, Frank Schöbel and Chris Doerk, were East German pop stars. (Letness has collected their records, too.)

At that time in the United States, teenagers were facing the draft, and protesting the Vietnam War, Letness pointed out. "But here's this truly alternate world."

That alternate world was a careful creation. The year "Hot Summer" was made, "1968 was not a time when the East German state was particularly friendly to cinematic experimentation," said Prof. Rick Mc Cormick, who teaches German cinema at the University of Minnesota. The government had "cracked down hard on the film industry in 1965-66, censoring nearly a full year's production," he said.

Rock 'n' roll was "still frowned on as Western or bourgeois decadence," he noted.

But the government knew how to market its message, using rock 'n' roll lite to masquerade as youth culture, slipping socialist ideology into songs.

At first, the message of "Hot Summer" wasn't clear to Letness. "The film doesn't hit you over the head, politically," he said. But after watching the musical a dozen times, he sees its subtle lesson: "There's a running theme of the group versus the individual and how being an individual … will get you in trouble."

Cinematic screenings of East German films have become more common, thanks to the DEFA Film Library at the University of Massachusetts Amherst, an archive and research center of filmmaking from the former East Germany. But theaters tend to stick to the classics: "The Legend of Paul and Paula," for example, or "Berlin — Schoenhauser Corner." Cinema-ready versions of the musicals are much rarer.

Letness had to bring a high-quality version of "Hot Summer" to the United States, paying to add English subtitles.

Because of Germany's complicated history, some filmgoers can't divorce the cinematic from the political, he noted. But Letness loves the film not only for its fascinating context but its fun.

"The world over, there are universal truths," Letness said. "Hot Summer" captures some of them: "Kids like to have fun, they like to party, and they like rock 'n' roll."

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