The kids repeat the words with smiles and enthusiasm — but they don’t understand that what they’re being told to say is “I am a black monster and my IQ is low.” The clip ignited outrage in China and beyond. But no-one ever answered the crucial questions: Why was this filmed? Where was it shot? Who made it? These questions send #BBCAfricaEye and #BBCEyeInvestigations reporters Runako Celina and Henry Mhango on a journey into a Chinese video-making industry that exploits vulnerable children across the continent.