The Nigerian Mafia: Johannesburg follows the gripping journey of Nollywood actor Uche Mbadiegwu, who escapes from Brazil with the help of a Sierra Leonean diplomat and makes his way to Johannesburg, South Africa. There, he crosses paths with Professor Bern Steyn, a renowned criminologist at the University of Johannesburg, who is researching a book on Radovan Krejčíř, a convicted Czech criminal operating in South Africa.

Meanwhile, Huan Lin Zhang, a Chinese businesswoman, regularly meets with Chuma Mpiga from the Department of Home Affairs at the Mongkok Chinese Restaurant in Bruma. Pastor Tim Cletus, a self-proclaimed Nigerian clergy, is deeply involved in visa racketeering and trafficking South African women. The Chinese community, eager to shut him down, hires Uche to take him out of business.

At the same time, Uche is recruited by Indian loan sharks to intimidate defaulters. However, his methods become excessively violent, causing tension with his employers.

Set against the underbelly of Johannesburg, The Nigerian Mafia: Johannesburg is a dark and intense tale of crime, drugs, violence, and power, entangled with racial tensions, corruption, and religion.