The lives of a small-time pimp and a vice squad officer collide as they navigate the moral ambiguities of London's underworld. Frankie Love operates within the illicit economy of prostitution while attempting to maintain a personal code of ethics, while Ted Justice struggles to balance his professional duties with his private romantic life. The narrative examines the friction between personal morality and institutional law, highlighting the hypocrisy inherent in both the criminal and legal systems. The prose maintains a gritty, observational tone that captures the specific social atmosphere of mid-century London.

Readers and critics often note the stark, unsentimental style that MacInnes employs to depict the London streets. Discussion frequently centers on the author's ability to humanize characters operating on the fringes of society without resorting to moralizing. Many highlight the effectiveness of the parallel narrative structure in exposing the blurred lines between those who enforce the law and those who break it. The book is recognized for its historical value as a document of a specific time and place in British urban history. Readers appreciate the lack of melodrama, finding the clinical observation of the characters' choices to be the most compelling aspect of the work.