In a moving film based around the 2005 suicide bombings in London, an unlikely friendship develops between a reclusive, prejudiced white woman from Guernsey and a towering African man who arrives in the city from France.
In "London River", the physical contrast between Mrs. Sommers, played by British star Brenda Blethyn, and Ousmane, played by Malian actor Sotigui Kouyate, is striking. They speak different languages. She is a Christian, he is a Muslim.
But through a common quest to find their children who go missing after the July 7, 2005 attacks, the strangers gradually become close and realise they have more in common than they ever would have imagined.
As well as desperately seeking news of their loved ones, neither of the missing children knew their fathers -- Ousmane left his family when his son was six, and Mr. Sommers was a navy officer killed in the 1982 Falklands War.
London River, directed by French-Algerian Rachid Bouchareb, is a portrait of the human suffering caused by violence, and how it is common to people of all backgrounds.
The movie, which has its premiere at the Berlin film festival today, was warmly applauded by journalists and critics at a press screening and Blethyn could be in the running for a best actress award at the prize ceremony on Saturday.
Mrs. Sommers comes to the teeming streets of London from the solitude of her isolated farm, and is taken aback by the ethnic diversity of the area her daughter Jane was living in.
MUCH IN COMMON
When she meets Ousmane, with whom she converses in French throughout the story, she is wary, but when she discovers a link between them her preconceptions fall away.
"She gets paranoid and suspicious and wants to know the truth, and it was an uncomfortable thing for her," Blethyn told a press conference. "I think the film is daring, I think it's good because of that. It touches the subject of prejudice.
"She found that Ousmane is on the same quest. She says at one point 'Our lives are not so different'. But two days earlier she perhaps thought they were very different and I think it brings some understanding. I'm proud of the film."
Bouchareb said he always had Kouyate in mind for the part of the silent but strong Ousmane. When he saw Blethyn in Mike Leigh's "Secrets & Lies", he knew she had to play Mrs. Sommers, and waited for a year until she was able to shoot the film.
The director, who worked with Kouyate on "Little Senegal", told reporters he had no specific message in the film, and only wanted to tell the tale of the relationship.
Some of the dialogue was improvised and the shooting was "a holiday" compared with the technical and logistical challenges of his last film, "Days of Glory", about the role of North African troops fighting for France in World War Two.