it's as well we tell no lies, so i'll sing you no lullaby
She dreams of monsters.
They assemble in hordes, creatures of darkness and fear. They are nothing so predictable as manticores and dragons; they have no truly defined shape at all, and it's only if she looks at them too closely that they start to take any form. They are nothingness, and if they devour her, she will cease to exist, and nopony will remember that she ever existed.
But she's not afraid. They are awful dreams incarnate, and she is supposed to fear them, but she doesn't. She has her friends to stand with her.
They stand behind her, her army. Mondrian the Bat, his well-gnawed orange wings at the ready to take flight with her. Stelluffy the Cat, pink and purple paws braced against the ground. Harmony the Bear, Gunther and Gretchen the Griffins, Meg the giant ancient dragon, moonlight glinting off her gold and green scales. With Favorite Blanket tied 'round her neck as a cape, flowing in the wind, and Pink Receiving Blanket and Fluffy Blanket wrapped around her as armor, her wings poking out from underneath them, she stands ready, facing the fearsome horde. In the dream, she has a horn, not just wings, and she holds a sword just like her father's in a telekinetic grip she doesn't have in real life, with blades of moonlight strapped to her wings, ready to deal death to the monsters of hatred, apathy and nonexistence.
Luna grins savagely at her opponents. Once again, the bad dreams have chosen the wrong filly to torment. By day, she might be merely a Princess of Equestria, not even a Crown Princess like her big sister. But when she sleeps, she imagines herself Princess of Dreams, a brave and ferocious warrior ready to do battle against any number of things that go bump in the night.
"Ready, soldiers?" she calls to her army of stuffed animals.
"Ready, Your Nightness!" they chorus back.
"Then let us attack! GO!"
She charges forward, her sword held in front of her, her cape flowing behind her as she flies. Her army bellows in the voices of a dozen different animals as they launch themselves against the darkness.
Chapter title comes from "No Lullaby" by Jethro Tull.