Marijuana's criminal status in the United States did not start with science; it started with fear of Mexican immigrants who brought the plant north in the early twentieth century. This first half of a two-part history traces how that xenophobia hardened into federal policy, as officials recast a mild intoxicant as a menace requiring criminal law rather than public health measures. Propaganda campaigns exaggerated marijuana's effects and tied it to immigrant and minority communities, building public support for prohibition even as contrary evidence from researchers and physicians was set aside. The film follows how political opportunism, more than any medical finding, drove lawmakers to treat marijuana as a matter for police rather than doctors, and how that choice began eroding civil liberties well before the drug war's later decades. It sets up the second part by laying out the origins of a policy the film argues was built on prejudice and misinformation rather than evidence.