A first-person narrator, a modest young woman newly qualified in nursing, recounts how a sudden declaration of passionate love at an elegant ball upends her cautious plans. Amid the glitter and a conspicuous diamond-wearing guest, an observant distinguished stranger and a curious fan draw attention that soon gives way to darker events. The narrative moves from social scene to mystery: missing items, unsettling discoveries, arrests, and methodical inquiries reveal clues by moonlight and behind closed doors. Gradually explanations emerge, exposing deception, questions of guilt and identity, and the layered motives that reshape the characters’ lives.