Mr. Six (2015) on Netflix

Plot summary

For years the man known as Mr. Six, whose formal name is Zhang Xuejun, was the kingpin of his Beijing neighborhood. The old code he kept has faded, and he now lives quietly in a narrow alley, all but forgotten. Word reaches him that his son Xiaobo has clashed with Xiaofei, a well-connected young leader of a street-racing gang, after Xiaobo scratches a Ferrari. Getting his son back would mean returning to a life he believed was over, and he steps up to defend the boy, trying to settle the debt through the old-school rules he still keeps and with help from friends of his earlier days.