One day, a heavy rain poured down on Gensokyo. Reimu Hakurei looked for shelter in a shop called "Kourindo," but all she found there was trouble. Rinnosuke Morichika, the owner of the shop, started acting strange and suddenly attacked her. Reimu's skills were no match for his newfound power, and she found herself on the ropes. She retreated back to her home, the Hakurei Shrine. Then, with the help of the sage, Kasen Ibaraki, she headed back to Kourindo to investigate the mysterious tower that had appeared there and bring Rinnosuke back to his senses. Now the curtains rise on a new incident to threaten Gensokyo, the battle over the Gold Sphere.