Y/n is in class 1A. She is an orphan and has been for a while. Her parents and her three year-old little sister died in a car accident when she was seven. Now that she is a teenager she tends to stay far away from children as they remind her of her little sister. One day on patrol, Kirishima and Bakugo run into a villain who ends up turning Bakugo into a baby. And the second Kirishima brings baby Bakugo into the common room he is obsessed with y/n.