This is episode 51 of 51 of The Princess Reclaims Her Crown. Play it below, then continue straight into the next episode — the whole season is free and needs no account.
The closing stretch of the season, where the arc pays off.
Princess Emily Carter returns to the palace but is mistreated by Noble Consort Sarah Wilson until the Emperor rescues her. At the Mid-Autumn banquet, she's accused of being a fake royal. She recites a poem, exposes the false blood test plot, reveals the Consort's crimes, and is named heir.