One day during her childhood, Willemina, a duke’s daughter, suddenly gains a stepbrother. Believing him to be her father’s illegitimate child, and seeing that he knows nothing about studies or etiquette, she treats him harshly while attempting to educate him. Yet Nigel never shows even a hint of displeasure. Instead, he follows her around devotedly, calling out, “Sister… Sister…” She is certain he must hate her — so why does he act like he adores her…? A slow-burn, doting love story between a quiet, sister-obsessed stepbrother and a strong-willed duke’s daughter.