In the first of two programmes, James looks at the effects of the drug on the streets of Britain, meeting a 17-year-old who smokes weed with his parents and a mum-of-three who uses cannabis to keep her emotions in check. He meets people who are growing cannabis illegally for themselves and goes out on patrol with a police drug squad as they clamp down on large-scale cannabis growers. He also travels to California, the first state in America to license cannabis for medicinal use.