Tōhō Momoko is an ordinary and unremarkable little girl. One day after school, she accidentally obtains a magical Flower Language Star Card Notebook. Through this notebook, Momoko discovers that there exist spirits in the world born from nature. These spirits take the form of beasts or humans and possess powerful natural forces; if left uncontrolled, they can cause a lot of trouble in our lives. However, there is a kind of person who can communicate with these spirits, use Star Cards to subdue them, and control and utilize their power—they are known as Star Card Masters. To solve the troubles caused by corrupted spirits, Tōhō Momoko works hard to learn the power of purifying spirits and becomes one of the Star Card Masters. She also learns that she carries the bloodline power of the Flower Language Princess, bearing the important mission of purifying corrupted spirits and saving them! In the process of subduing and understanding the spirits, she gains two companions—Ōyuki and Gen Noichi. Together, they face dangers and hardships, learning courage, perseverance, tolerance, and love, growing into confident and beautiful Star Card Masters who protect everyone.