This documentary covers a whole lot of ground. It deals with every historical and contemporary aspect of hemp usage and cultivation (mainly in the U.S.), which turns out to be a lot.
From describing the production of a fiber much more durable and economic than wood, the documentary discusses hemps multilateral uses as e.g. food products, as a non-polluting fuel and as a pharmaceutical product with much less grievous side-effects than chemical pharmaceutical products.
The film also investigates why America went from a country which produced vast quantities of the non-narcotic industrial hemp, to the complete ban on hemp production in 1938.
This story in particular is interesting, and it points out that the large oil-based industries actually had a key role in the aforementioned ban. Food for thought! The conclusion of the documentary could be that hemp may prove to be a valid alternative to both oil and wood in the future.