Sonita

The winner of both the Grand Jury Prize and the Audience Award at Sundance Film Festival - adding to the Amsterdam International Documentary Festival award it picked up last year - the titular aspiring rapper could certainly teach the Spice Girls a thing or two about "girl power". Her story is not merely a case of overcoming adversity but of actively looking beyond immediate bleak circumstances in a bid to make her own destiny. The film is also wrapped up in larger examination of the documentary form, as director Rokhsareh Ghaemmaghami gets caught on the horns of a dilemma when Sonita turns to her for help. There's often a question mark over how involved a documentarian has become with their subject and here Ghaemmaghami confronts the issue head on, showing how she becomes not just a recorder of what happens but a catalyst for change.

Born in Afghanistan, when we meet 18-year-old Sonita she has already been forced to move country once, fleeing with her family to Iran as a refugee. Living in Tehran for 10 years with no legal papers, she cleans at a charity for street children, who help her scratch together an education, while spending her off hours dreaming of making it as a rap star. It's no empty-headed desire as her way with words shows, particularly in the hard-hitting Brides For Sale – with an equally hard-hitting video shot by Ghaemmaghami showing a beaten bride – that brims with both anger and sadness.

We learn about Sonita's life piecemeal because this is a documentary that has a hold tight rather than arm's length approach. Ghaemmaghami is already involved in changing Sonita's life with that pop video but when the young girl sees her mum for the first time in eight years, things become very complicated. Her mum has come to tell her she must marry, for $9000, so that her brother can afford to buy his bride, as is the tradition in Afghanistan. In some ways, Sonita might be considered lucky – she was first earmarked for sale at 10 years old but the marriage fell through. "Would you buy me?" she asks the director. It's the $9000 question and one which causes Ghaemmaghami some consternation before she, just like Sonita's mum, who, it must be remembered, is only following a long line of tradition, finds she has no other option.

What follows is the tense story of Sonita's return to Afghanistan in a bid to get papers to carve out a new, third life. To say more would be to spoil the trip as we, like Ghaemmaghami become entangled in the life of this forthright, feisty young woman. Whether she will become the next Rihanna is debatable but you sense that, no matter what she chooses to do, she will be driven to succeed.