Desert: Mama, whats this one about? Who's the pretty pony?

Luna: That is… our sister.

Desert: Why does she have a window?

Luna: As sister and I grew older, many of our old friends and loved ones left us while we remained. Fearful that’s we’d forget their faces, I proposed that we make something to remember them by. Thus these windows. Over the centuries, many windows were crafted by us. So, so many…

Desert:… I-its really pretty, mama.

Luna: [half listening] It’s nothing but hollow sentiments. Even immortalized in glass, they are gone forever and now Tia… Tia too has left me all alone…

Desert: Mama? ***

Luna never really gets over the deaths of those long gone. Despite everything, she misses them all. She remembers everything about them, their faces, their colors, what food they liked and how they lived. The stain glass windows was just a way to make sure others wouldn't forget them. She had hoped and prayed she'd never have to make one of Celestia, because surely her sister would never leave her behind.

Yet she did.

Now she has to explain to her daughter, Desert Moon, who the pretty pony is when she should have be able to meet her.

Note: The sun is setting so Deserts mane is shifting from black to white.