Precious Ramotswe and Grace Makutsi, Gaborone's No. 1 Lady Detectives, do not always agree on important issues - one being the complex male psyche. Grace believes that food is the source of men's happiness, while Precious takes a more nuanced view: men are not so different from women, they want to be loved and needed, too. It is pride that is so often their undoing.

Mma Ramotswe is reminded of this when ­her husband, J. L. B. Matekoni, is offered a daunting business opportunity; one which, if it fails, threatens their existing livelihood, including the detective agency. Somehow, Precious must guide her husband to the right decision, while being mindful of how much he wants The Joy and Light Bus Company to succeed.

Meanwhile, there are other problems to solve. A wealthy client's elderly father has changed his will, making his devoted live-in nurse a significant beneficiary, and the ladies are tasked with uncovering the woman as a fraud. And then there is the disturbing rumoured maltreatment of children living and working on a local farm, which a concerned Mma Ramotswe is intent on investigating.

Professional and moral duty battles with female instinct and Mma Ramotswe is determined not to jump to conclusions until she has all the facts. She knows only too well how cunning people can be. After all, she herself is not beyond a little trickery - especially when it comes to righting wrongs and seeing justice served, or when innocent lives are at stake.