Precious Ramotswe is Botswana's first and only female private detective. One day she is visited by an American woman, whose son died a mysterious death 10 years ago, and she agrees to investigate the case. Meanwhile her fiancé, Mr J.L.B. Matekoni, is talked into looking after two orphans.
Can the engagement now survive? Moreover, his housemaid is plotting to get rid of Precious so she can continue to meet her male “friends” at Mr. Matekoni's house during the day. And finally Precious’s secretary, Mma Makutsi, is promoted to assistant detective and gets her first case: a husband wants to know if his wife is being unfaithful. How will it all turn out?