When Shiemi was young, her mother was very busy with the Exorcist Supplies Store, so her grandmother took care of her. This nurtured a close relationship between Shiemi and her grandmother. Shiemi helped her grandmother in their garden, and learned how and when to grow each plant. Her grandmother told her about the Amahara Garden, a garden created by god that has all the plants in the world.
When Shiemi was about 13 years old, Shiro Fujimoto brought Yukio Okumura, a recently qualified Exorcist, to the shop. Yukio was very nervous despite encouragement from Shiro. Shiemi's mother called her to come meet Yukio and, after saying hello, Shiemi fled because she was shy. Later, as Shiro and Yukio were leaving, Shiemi reappeared and gave Yukio a four leaf clover charm. However, she kept referring to Yukio as "sensei," which he found to be too formal since they were the same age. At that, Shiemi gave him the nickname "Yuki-chan," which made Yukio blush, but he accepted it.
A year or so later, her grandmother needed help covering the grapes, but upon hearing that Shiemi had planned to search for the Garden that day, she told Shiemi to go, but to be back before sunset. When Shiemi came back, she found that her grandmother had attempted to cover the grapes by herself and had been killed. Her guilt drove her to try to take care of the garden by herself, but there were some things she couldn't do on her own. She was approached by a Demon that had possessed a flower, and the Demon offered its help in exchange for Shiemi to stay in the garden forever.