The theme of "A Walk in the Night" is the way in which South African racism and the apartheid system demean and dehumanize whites and blacks alike. After Michael Adonis is fired for requesting a bathroom break from the white foreman in his factory (who refuses him), he is seething with anger. The policemen in his urban district, District Six in Cape Town, are all white and are bent on harassing the black population. As Michael passes them, he thinks, "You learned from experience to gaze at some spot on their uniforms... but never into their eyes, for that would be taken as an affront to them." The policemen spend their time accosting the locals rather than helping them. In addition, the district is overrun by American sailors, who make a beeline to the whore houses and are otherwise disruptive.
For all these reasons, Michael walks about with a "little knot of rage" inside him. He mistakenly kills Uncle Doughty, a white neighbor, and thinks, "Well, he didn't have no right living here with us Coloreds." In the aftermath of the murder, Constable Raalt, a white man, thinks that Willieboy killed Doughty, and, incensed by the murder of a white man, he hunts Willieboy down and shoots him. The story is about the injustice and brutality of the apartheid system.
This story, covering the events of one night, shows with brutal and relentless honesty how corruption begets corruption. Beginning with the injustice perpetrated against Michael at work, each small unfair act leads to larger and larger problems. The discrimination shown to Michael at work spirals into the impulsive killing of Doughty. Instead of being shamed by his drunken action, Michael is able to use the racist attitudes of society to justify his actions:
"[he has] no right living here with us Coloreds."
Michael, who began the story being heckled as "a good boy" ends up in a gang. Willieboy, an innocent who runs scared from a dead body, ends up getting shot. Willie's flashbacks when he is on the run demonstrate that his mother - a victim of abuse at his father's hands - turns her son into a victim by beating him. Gaining self-respect in this corrupt world comes from turning on your neighbor, as John Abrahams demonstrates by turning in and describing Willieboy. The message overall is negative; La Guma is demonstrating the inevitable corruption in this racist society.