Tessa is the wife of a minor British diplomat in Nairobi, and an active campaigner for human rights. When she is murdered, her husband Justin rouses himself from his careful indifference and, unravelling the threads that led to her death, sets off in her footsteps. His journey will take him around the world, to a village retreat in Italy, a non-government organisation in Germany, an ostracised scientist in Canada, a food distribution area in southern Sudan, and in the end back to Kenya and the scene of Tessa's death.