Luna Ishikawa is a high school girl and is also a vampire. She has a mysterious air about her, and a domineering presence. As a transfer student, she's the center of attention in class. Everyone admires her! Tatsuya Ootori, a faceless background character in her class, accidentally found out that she has a different side of her. She was so bad at sucking blood...and would turn to a small, cute creature like a baby when trying to do so. Before Ootori knew it, he suggested becoming a practice partner on sucking blood. Small Luna was so cute that he couldn't resist...to be her "mom"!