Early one morning, Thomas Pitt is summoned to the offices of Victor Narraway, head of the Secret Service in Queen Victoria's vast empire. An ex-army officer and promising young diplomat has been shot at Eden Lodge, home of the Egyptian mistress of a senior cabinet minister, Saville Ryerson, and the prime suspect is the woman herself.

When Pitt visits the scene of the murder, however, he finds that some things don't add up. Why did the Eyptian woman have a gun, and if she needed protection, from whom? Is her lover lying to protect her, or himself? When the Eyptian Ambassador puts in a call to Prime Minister Gladstone, it seems that a major diplomatic row is brewing.

Meanwhile Charlotte Pitt is more concerned about her husband's safety. Thomas is convinced that Narraway knows more about this case than he claims, and Charlotte fears that he could be involved with the Inner Circle, the secret organistion that destroyed Pitt's career in the Metropolitan Police and very nearly cost him his life. Can Pitt tread the tense diplomatic tightrope between protecting justice, the security of his country, and the safety of his family?