A 16-year-old Black kid walks into a gas station in Stockton, Calif. to buy gummy worms for his little sister. When the teen gets in an argument with the clerk over a damaged dollar bill, a white officer in plainclothes decides to intervene — with force. We bring you an episode of On Our Watch, a new podcast from NPR and KQED that traces the ripple effects of this incident over the next 10 years in a department trying to address racism and bias.