Ciara, the daughter of a court librarian, is mistaken for Princess Atira and brought before the queen after the real princess goes missing. Ciara and Atira look identical, so Ciara begins impersonating the princess at social events as her body double. At night, Ciara acts as the queen's secret agent and assassin to root out threats. As complications arise from a foreign prince's arrival and the queen's search for a husband for Atira, it is revealed that both Ciara and the prince carry rare, powerful secrets that could get them killed if discovered. Ciara's secret legacy and powers have not been seen for over a decade and end up sparking rebellion in the kingdom.