A group of men is playing cards in a hostel. Following a suggestion that they go to the pictures, one of the men says that he has something better do. He explains that he met a girl by chance after leaving work the previous evening, and tells his friends that he is meeting up with her again. One of the others warns him to be careful, as he knows nothing about her. He meets up with the girl, walks through a wood with her, and the two begin to kiss...

A few days later, the man feels ill, and is advised to go to the doctor. He walks around the town, trying to pluck up the courage, and sees a poster advertising a lecture sponsored by the British Social Hygiene Council on 'Problems of life and health'. At the lecture, a doctor relates case histories of venereal disease:

• A sailor on leave infects his wife and daughter.
• A farm labourer develops inflammation of the knee joint which results in him losing his job.
• A lorry driver develops locomotor ataxia which makes it difficult for him to use his feet and legs. Whilst driving he is unable to brake quickly enough and is not only injured himself but also kills someone.
• A city clerk contracts General Paralysis of the Insane, a condition which makes him think he is wealthier than he actually is, resulting in his being taken to a mental home. His son then contracts congenital syphilis and the family becomes destitute.
• A steel worker neglects treatment and falls off a girder due to heart disease.

The doctor advises the audience to take treatment if they think they are in need of it. After the lecture the man stays behind and talks to the doctor and is given a hospital appointment.