Istanbul, Turkey (CNN) -- The movie "No One Knows About Persian Cats" has no sex or drugs, just lots of Iranian rock and roll.
It tells the story of two young lovers with an almost childish dream: to perform a rock concert in a country where art and music are strictly censored.
"Persian Cats" was shot in Tehran last year in 18 days. The director had to make it quickly and quietly because he did not have permission from the Ministry of Culture and Islamic Guidance to shoot the film.
"We were afraid. And I couldn't have time to practice with the actors and actresses, never," said director Bahman Ghobadi. "When we went to the location (to film) we couldn't come back a second time. Because I was worried ... really we had a lot of stress."
Watch a scene from the film featuring fast-talking hustler Nader
Ghobadi said he feared the Ministry of Culture and the police would target his young actors.
Video: Nader in the police station Video: Heavy metal band Video: Ashkan and Negar
Using this guerilla-style approach to filmmaking, Ghobadi focused a lens on Iran's struggling underground music scene. The 41-year-old director compared the long-haired young musicians to Persian cats, because he said they get more respect and love outside the country than at home.
"Look at the women and girls," Ghobadi said. "They cannot sing. They cannot play the music. They cannot make a concert, because the voice of women is haram (against Islam) in Iran."
Harassed by religious police and government censors who denounce Western-influenced culture as "un-Islamic," the films' star-crossed, indie-rock lovers Ashkan and Negar decide their only hope for artistic freedom lies in London.
Watch Ashkan and Negar perform their song "Human Jungle"
Desperate to escape the restrictions of the Islamic Republic, they set about trying to purchase black-market passports and visas -- and eventually become victims of their country's repressive moral order.
Since the film was banned in Iran, Ghobadi debuted "Persian Cats" last May at the 2009 Cannes Film Festival, where it won a special jury prize.
Watch heavy metal band Nikaein perform in a cow shed
A ministry official tells CNN, on condition of anonymity, that Ghobadi did not have a permit to make the film and therefore the film was banned in Iran. When asked why his filming permit was blocked, the official only said, "there were special reasons for it."
One of the screenwriters was Iranian-American journalist Roxana Saberi, who was arrested and jailed in Iran on espionage charges. She was released at about the same time as the film was being shown in Cannes.
After his own run-ins with Iranian authorities, Ghobadi now lives in exile, too. He spoke to CNN after "Persian Cats" was screened at Istanbul's Independent Film Festival across the border from Iran in neighboring Turkey.
The director is a short man with graying hair who speaks English with boyish enthusiasm and the sing-song accent of a native Persian speaker.
He is also an unabashedly proud ethnic Kurd, whose earlier feature films "Half Moon," "A Time for Drunken Horses" and "Turtles Can Fly" focused on war-torn Kurdish communities in Iran and Iraq.
The Iranian government is now the target of much of Ghobadi's criticism, particularly after its crackdown on pro-democracy protesters following last summer's presidential elections. Many journalists and artists associated with the opposition "Green Movement" have been arrested in the aftermath.
See more of CNN's in-depth coverage of the protests in Iran
Iranian police raided the Tehran home of another prominent filmmaker, Jafar Panahi, on March 2. Panahi had been living under a travel ban after he was briefly detained for attending the memorial of Neda Agha Soltan, a young woman who was shot and killed last summer at an opposition protest. The Iranian government has denied accusations that security forces killed Soltan, arguing that the bullet found in her body is not one used by Iranian security forces. A government-led investigation is still underway.
Panahi was arrested along with at least a dozen relatives and friends, including Mehdi Pourmusa, an assistant director on "Persian Cats." Iranian officials say Panahi and his guests were not detained for artistic or political reasons.
"A government which is so scared of artists -- I don't think that kind of government rests on solid pillars," Ghobadi said. "It depends on a piece of paper. And as easy as that it can blow away like a piece of paper."
Ghobadi said one character in "Persian Cats," the fast-talking bootleg DVD distributor Nader, is autobiographical. In one memorable scene, Nader appears before an angry Islamic court judge. Using a combination of tears, groveling and Koranic exhortations, Nader manages to talk his way out of getting flogged for being caught with hundreds of Hollywood films and a bottle of alcohol.
"You have to lie in Iran," Ghobadi said. "From the top of society to the bottom, they teach you lying ... I always lied to get permission to film."
There are also comic touches in "Persian Cats." In one scene, mooing cows compete with thrashing electric guitars and cymbals when a heavy metal band is forced to rehearse at a dairy farm that reeks of manure.
There are defiant notes, too.
"This is the voice of a man whose hopes don't live in a dead end," growls the heavy metal band's singer.
"My wild cries tear down the fence," he sings in Farsi. "My words were not criminal though they were hanged. The fences around your mind cannot contain me ... There's no room in your cage for me."
The lyrics tap into the frustration felt by many young Iranians, some of whom risked arrest or worse over last year's protests against the government.
Ghobadi said these young Iranians represent his greatest hope for eventually being able to return to the country of his birth.
"These young people, this is the real Iran," Ghobadi said. "They are brave and they want change. I am following them."
Many of the musicians featured in "Persian Cats" appear to have followed the director's example, opting for artistic freedom in exile over censorship and repression at home. Since the film's 2009 debut, at least half of the musicians profiled in "Persian Cats" have left Iran, Ghobadi said.