The Absence (2009)

Adama Diop is a successful scientist, living in Paris. After 15 years away, he travels to his hometown in Senegal to visit his aged grandmother and his semi-deaf mute sister Aicha. Aicha is still traumatized about their mother's death, who died as she was giving birth to her. But the true extent of Aicha's mental state only becomes apparent when Adama discovers she is working as a prostitute, amidst a seedy underworld of gangsters, drugs and crime. Adama's discovery leads to a gripping thriller as he struggles to free Aicha from the sinister world into which she has descended.