The book starts out with Mma Ramotswe talking to her fiance, Mr. J.L.B. Matekoni, about the future of her assistant, Mma Grace Makutsi, who seems to have difficulty finding suitable men. When Mma Ramotswe talks to Mma Makutsi about this, the latter takes on a demeanor of defeat, and the conversation ends at that.
The focus shifts to Mr. J.L.B. Matekoni's garage, and more specifically, the apprentices, formerly described as lazy young men "always looking at girls." However, there is quite a change in the younger apprentice, who seems to have found religion and is now uninterested in discussing girls, to the chagrin of his fellow apprentice.
When Mma Ramotswe arrives at home, both of her foster children seem down, with Motholeli and Puso being the subject of mainly verbal bullying. Motheleli seems to get over this, however Puso projects his anger at his foster parents and says that he "hates them."
To increase her income, Mma Makutsi decides to open a typing school just for men, because, in her view, men usually cannot or don't want to type because they don't want to be bettered by women or do not want to be seen doing "woman's work". She manages to procure typewriters from her alma mater, the Botswana Secretarial College, and finds a place to teach at the younger apprentice's church. This business is very successful.
Mma Makutsi then gets involved with one of her students, a Mr. Bernard Selelipeng, a married man passing himself off as divorced. Consequent to parallel developments involving Mma Ramotswe, Mr. Selelipeng is forced to break off with Mma Makutsi (see below).
To solve the current problem with Puso, Mma Ramotswe goes to the orphanage to consult the matron, Mma Silvia Potokwane, about him. Mma Potokwane's advises having Mr J.L.B Matekoni act as more of a father to the boy. Mr. J.L.B Matekoni does this, with apparently favorable results.
The story ends with a picnic, attended by the apprentices, Mma Ramotswe, Mma Makutsi, Mr. J.L.B. Matekoni, Rra and Mma Potokwane, Mma Boko, and Mr. Molefelo and his family (see below).
A rival detective agency, called the Satisfaction Guaranteed Agency, has come to town. The business is owned by Cephas Buthelezi, "Ex-CID, Ex-New York, Ex-cellent!". Whether he has actually been to New York is questionable, since he never answers Mma Makutsi's questions about it directly. He is of Zulu origin. His advertising is extremely derogatory towards the No. 1 Agency in a somewhat sideways manner; he implies that you need a man to do detective work properly. However, his hubris is repaid, and at the end of the book he comes into the No. 1 Ladies' Detective Agency and says he is giving up the business.
The Molefelo Case :
Mr. Molefelo is a prosperous civil engineer in Lobatse who is also the proprietor of a hotel and landowner with an ostrich ranch. As a young student at the Botswana Technical College in Gaborone, he had a girlfriend whom he had made pregnant. In order to pay for an abortion (which is illegal in Botswana) he had to pay 100 pula (about $20). Since he had no way to get money, he stole a radio from his host family, the Tsolamoseses. After the abortion, he got angry with his girlfriend and broke up with her.
After nearly getting killed by ostrich rustlers, Molefelo wants to set his life straight and apologize to both his girlfriend (named Tebogoå Bathopi) and the Tsolamoseses, and enlists Mma Ramotswe's help in finding them.
The Selelipeng Case :
Mma Selelipeng comes to the No. 1 Ladies' Detective Agency to confide in Mma Ramotswe that her husband is probably cheating on her. She also says that she tried Mr. Buthelezi's agency, but they did a most "unsatisfactory" job. Mma Ramotswe must now do a balancing act between satisfying the client and protecting Mma Makutsi.