When Jun’s mother took her child to the department store to buy a backpack for kindergarten, they both died in a car accident. Jun’s spirit lingered, wishing for a backpack, and was found by Tsubasa’s father, who claimed to have a backpack for the child. He kept the pre-school child’s spirit in a bottle and sent it along with a backpack that got heavier every year as it desired to be carried on one’s back since it was not used by another child who ended up dying of a sickness, to Tsubasa by mail. However, Jun was not happy with that backpack and would complain about having been tricked, so the backpack went on Tsubasa’s back and would chase the pre-schooler spirit. Sakura figures that the problem is the color of the backpack since Jun turns out to be a girl, so Rinne uses red spray on the black backpack, satisfying Jun and thus the backpack. Although it was a first step to satisfy Jun and allow her to rest, since she also wants to buy dresses as her mother had promised her.
- She would be the first ghost and the backpack the third item Tsubasa would receive from his father through home delivery, which bring a case to be solved.