At Botswana's No 1 Ladies' Detective Agency, Precious Ramotswe and Grace Makutsi are intrigued by the troubling dismissal of an employee at a thriving local business. The ladies proceed with investigations as they are inclined to do - with Mma Makutsi's customary vigour, and Mma Ramotswe's rather more subtle caution. Soon enough, interesting discoveries are made... marital subterfuge, undue influence and commercial chicanery! Clearly, there is more to this dismissal than at first imagined.

While Mma Makutsi's focus, as self-appointed Principal Investigating Officer, is firmly on the case, Mma Ramotswe's attention is diverted by personal matters. Not only has her disgraced ex-husband reappeared in town, but she has stumbled on an unsettling family secret of her own - one that might threaten what she holds closest to her heart.

As Precious contemplates this painful possibility, she must draw on her strength and compassion and confront The House of Unexpected Sisters. And for both Mma Makutsi and Mma Ramotswe, the wise words of their mentor Clovis Andersen - 'the needle swings in confusing ways' - have never been more prescient . . .