Life, this movie informs us at the beginning, is unhappy and almost everyone is miserable. Things like Heroin make it seem briefly good, and so, for centuries, governments have outlawed these drugs, except for Queen Victoria, who got Hong Kong for her efforts.
After that blinkworthy introduction by the voice of Paul Newman, we listen to a number of police officers and DEA agents who tell us how easy it is to smuggle Horse into the United States and where to buy it in Manhattan. We then see the horrible ravages wrought by this modern plague, which seem to consist of one man jabbing a needle into his thigh, garbage piled in front of a poorly maintained tenement building and people sitting around a Synanon center, who talk about communicating.
Perhaps the people who made this public service movie thought that everyone knew why Heroin is so bad, but it all seems couched in terms of money and the thought inevitably arises -- or, at least, it occurred to me -- that if the stuff were not so expensive, then people would not have to steal to buy it, and a Heroin habit would be not much more trouble than maintaining a habit of drinking a six-pack of Diet Coca-Cola a day. Perhaps they thought showing the ravages of drug use would be too graphic. Perhaps they thought a two-reel Public Service Announcement did not permit these details.
All I know is that if this was intended to convince people not to do drugs, the only clear barrier would be the expense and jail. Maybe we would be better off if we just legalized all of these things....