Cautionary tale features a fictionalized and highly exaggerated take on the use of marijuana. A trio of drug dealers lead innocent teenagers to become addicted to "reefer" cigarettes by holding wild parties with jazz music.

A laundry man parks his horse-drawn cart to make a delivery. While he is inside, his horse sees a bag of oats and starts to eat them. By the time the man comes back outside, the horse has eaten a whole bag of oats, and has so much energy that he begins to race out of control.