She’s an airhead, who tends to borrow her sister’s clothes without permission and carelessly soil them, and has such a rashness that she put 2 different shoes.
10 days ago, she accidentally soiled her sister’s newest dress with ketchup, so she hurried to the house and hid it in her closet, but then decided to take it to the cleaners. However, without noticing due to her rashness, she put a towel with red flowers in her bag instead, and promptly tripped and fell, getting a bump at a crosswalk. Her disembodied spirit left her body, which was taken to the hospital, as she was very determined to have the dress cleaned, and would continuously go to the cleaners, asking for the dress to be cleaned, though that dress would always disappear as she was not really holding it.
Sakura witnessed her spirit when she went to the cleaners and informed Rinne, who would investigate. In the process, they meet her sister, who ends up knowing what Ayu did to her dress but was more concerned about her unconscious situation, and Ayu wakes up at the hospital, after Rinne and Sakura convince her spirit that she can return to her body since she’s not dead. However, she'd get another bump on her head, as her sister badly scolded her for all the dresses she soiled.