The Fake Phoenix Took the Palace

A daughter of the house is expected at the palace. The family will not part with the one they favor, so they take the illegitimate girl who works in their kitchens, have her face changed to match, and send her in under the other girl's name. Her mother was framed by that same household years earlier. She was imprisoned for it and died there under torture, and afterward the girl was kept on in her father's house as the lowest of the servants, with everyone in it knowing whose child she was. She goes along with the substitution and says nothing about the rest. In the harem she gets the emperor's attention and keeps it, and she uses what comes with it against the family that sent her there.