The Cripple Prince's Lucky Star

To hold his position at court, the crown prince produces a girl he calls his legitimate daughter and has her recognised as a child born with fortune. The daughter he actually fathered he had abandoned himself, on a wet night, when she was small enough to be carried out and left. That child is Ivory, who had been a spirit of good fortune in the heavens before she was born into the family. She is found close to death by the prince the capital mocks for his ruined leg, a man with no office and no standing, and she grows up in his house. The luck she carries attaches to the people around her: his leg mends, the Emperor comes through an illness that should have finished him, and disasters that were coming for the country do not land. She is old enough by then to start asking where she came from, and what she finds runs straight into the fight over the succession. The girl carrying her name at the palace has nothing behind the claim, and the crown prince has to keep the substitution standing while the court begins to look at it.