Being Princess of the Night is something Luna was born to do.

She hasn't always been perfect at it, and the role has required her to do things she doesn't like to think about, but she does them anyway. Better her than her sister, the wise, perfect, bright as noon-day-sun Celestia, in whom there is no darkness at all.

Or so Luna thinks, until the return of an ancient evil forces her to re-examine several of her assumptions. For Luna isn't the only one with a dark side.