When the flamboyant president of Ng'ombwana visits London, Chief Superintendent Roderick Alleyn must navigate a high-stakes security operation to protect his former schoolmate from a lethal threat. As the embassy grounds become a fortress of police presence, an assassin manages to strike, forcing Alleyn to untangle a web of political intrigue and personal vendettas. The narrative follows a classic procedural framework, balancing the rigid protocols of Scotland Yard against the volatile atmosphere of international diplomacy. Alleyn must contend with competing interests from Special Branch and the president's own tribal court, all while searching for a killer hidden in plain sight.

This novel is widely regarded as a quintessential example of Ngaio Marsh’s ability to blend high-society settings with complex, methodical police work. Readers often highlight the author's sharp wit and the clever integration of the president's unique background into the traditional mystery format. The presence of the cat, Lucy Lockett, is frequently noted as a charming, albeit unconventional, addition that provides a unique perspective on the unfolding investigation. Critics and fans alike appreciate the technical precision of the procedural elements, which ground the more theatrical aspects of the plot in a believable reality. The work remains a staple for those who enjoy the classic British detective tradition with a touch of international flair.