Luna's main duty involves looking into the dream of foals, giving them hope for a new day. However, her reach goes beyond Equestria, and she continually leaves to watch the dreams of other species.

But none are more interesting than the dreams of the changelings.

She discovers their dreams are filled love and kindness and hope. When she investigates the mind of Queen Chrysalis, she discovers the reason behind the Canterlot Siege.

And her sister's dark past.

Luna soon realizes her life was a lie.