Adele, a laundress at a rural mill, was adopted as a child and her origins remain a mystery. When the royal court comes searching, she unexpectedly reveals her ability to read, catching the princess's attention. An old blue swaddling blanket uncovers a long-buried truth: she is the twin sister who was swapped with the princess at birth. Thrust into a royal upheaval overnight, the ordinary laundress sets out on a brand-new fate of her own, caught between family love and royal power.
