Caroline, a lady's maid, unexpectedly spends a night with King Sebastian and becomes pregnant with the royal heir. However, her scheming best friend Natalie takes her place by claiming credit for the night, using a handkerchief Caroline left behind. Forced to stay by the side of the distrustful, highly possessive king as a personal attendant, Caroline repeatedly outwits danger with her intelligence amid the joint persecution of the vicious lady-in-waiting Sienna and Natalie. When the truth about the car accident where she risked her life to save the king, the poisoning plot, and her pregnancy all come to light one after another, King Sebastian is overcome with remorse. At a grand ceremony, he publicly executes the fake best friend and majestically marries his true love, Caroline.
