Underdog Knight 2008 Lao san is a highly motivated navy man In saving a friend from drowning he suffers hypoxia The lack of oxygen causes permanent brain damage and he is no longer able to function to a normal level of intelligence After being discharged from the navy he remains caught obsessively in the training he received With only a young deaf boy for a friend he moves around the city fighting crime and trying to teach petty thieves the simple lessons of right and wrong using his martial arts background