One bright morning, Precious Ramotswe - head of Botswana's No. 1 Ladies' Detective Agency - receives a visitor: a woman from Australia. This woman asks Precious to take on a case: to find the nursemaid who raised her during her childhood in Botswana. The woman wants to thank her for being such an important part of her life. Precious has a history of successfully solving cases, but this one proves difficult and throws up a number of surprises and challenges.

Back in her office, next door to the Speedy Motors Garage on Twokleng Road, Precious also has a team to manage: Mr Polopetsi, a part-time science teacher and new assistant at the agency; she mentors Charlie, a former apprentice and young man too handsome and charming for his own good - a man who has gotten himself in deep water; and then there is Precious's tumultuous but heart-warming friendship with her co-director, the fiery Grace Makutsi.