This is the first film released in Iran from director Dariush Mehrjui since his earlier films, The Cowand The Postman, The Cycle looks critically at corruption in the medical services provided by the city for the poor.

An energetic seventeen-year-old has come with his sick and complaining father from the countryside, but he cannot get him admitted to hospital A pretty nurse helps the boy to get his father examined by a doctor, but he is still not admitted.

A callous businessman, who makes a living from supplying plasma to the hospital, persuades the boy to donate blood,then introduces him to a system of obtaining blood from the drugged, the sick and the poor. He becomes as unscrupulous as his new master, finding new victims to donate blood, and planning to obstruct the hospital's attempts to construct its own blood donation laboratory.

The film's theme of personal corruption is underscored by the visual contrasts between the new building boom in Tehran and the wretched hovels of the poor districts.