Mrs. Harris, a London charwoman with a penchant for adventure, travels to New York City to reunite a young couple and navigate the complexities of American society. Driven by her characteristic optimism and sense of duty, Mrs. Harris finds herself navigating the stark cultural differences between post-war London and the fast-paced, often impersonal environment of New York. She encounters various social strata, from the wealthy elite to the struggling working class, while attempting to resolve a romantic entanglement that brought her across the Atlantic. The narrative follows a linear progression, utilizing a third-person perspective that highlights the protagonist's pragmatic yet whimsical approach to life's obstacles.

Readers frequently highlight the charm and resilience of the protagonist as the primary draw of the narrative. Discussion often centers on the author's ability to capture the social nuances of the era through a lighthearted yet observant lens. Critics note that the pacing remains steady, prioritizing character growth over complex plot twists. The book is often praised for its gentle humor and the way it addresses the human condition without resorting to overly cynical tropes. Many readers find the depiction of New York through the eyes of a visitor to be both nostalgic and insightful.