The Circular Staircase is narrated by Rachel Innes, a formidable middle-aged woman who rents Sunnyside for the summer with her niece Gertrude and nephew Halsey. Before the household can settle, Arnold Armstrong is shot at the foot of the house's circular staircase. Halsey and Gertrude both conceal information, Gertrude's fiancé Jack Bailey is tied to a collapsed bank, and repeated intruders search the supposedly empty Armstrong home.
Rinehart layers domestic comedy over genuine menace. Rachel's battles with her alarmist maid Liddy make the first-person voice unusually lively, while the plot steadily adds a missing bank fortune, a false burial, an illegitimate child, a secret engagement, a disguised gardener, and a room hidden between two fireplaces. The solution is less a single deduction than the convergence of several crimes committed for different reasons.
Modern readers may find the racial dialect and stereotypes surrounding Black servants offensive, and some coincidences depend on characters withholding facts for melodramatic reasons. Even so, the novel's combination of practical heroine, endangered household, Gothic architecture, and financial conspiracy helped define a durable mystery form. Rachel remains the book's chief pleasure: skeptical, nosy, brave, and funnier than the danger allows.
