The Pakistani city of Karachi is one of the biggest in the world - and now one of the most dangerous. For more than two years, it has seen an onslaught of kidnappings, bombings and targeted assassinations by Taliban militants. The police are now fighting back, but they are understaffed, under-resourced and up against a deadly enemy. More than 160 police officers have been killed in the line of duty in just 12 months. Mobeen Azhar joins Police Superintendent Ijaz and his team of Taliban Hunters as they try to regain control of the city.