Scarlet Revenge: The Emperor's Love

Bandits kill the parents of Clara David, whose family is the leading supplier to the royal household. The men who did it were carrying the waist tokens of the imperial guard, so Clara concludes the Emperor ordered it. To get inside the palace she remakes herself into a courtesan, takes a new name, and becomes the most sought-after woman in the capital. Inside, she meets a guard she cannot place, and against her own plans she falls for him. He is the Emperor, out of his robes and moving through the palace unrecognized. She keeps investigating the murder while carrying on with him, and each thing she turns up sits badly against what she assumed at the start. The tokens the killers carried came from somewhere, and someone in the imperial family had reason to see her parents dead and reason to make the Emperor look responsible for it.