This book tells the story of the protagonist, 12-year-old Yao Lili, who found a magic book with a moon on the cover under her desk. When her hand touched the book, the book opened by itself, and a star key fell into Lili's hand. A girl with wings on her head also flew out of the book, claiming to be Inanna Annabell. She is a moon magician who controls the power of the moon, and Lili is the chosen user of the power of the stars. Under Annabel's guidance, Lili continued to upgrade her magic power. Strange things keep happening around Kelili, and a powerful solar force seems to be the source of these strange things. On the way to upgrade, Lili became good friends with the mysterious Oberon and the beautiful Mary Sue. But Annabel discovered that Oberon's body had an imperceptible aura of the sun. As strange things become more and more frequent, Lili must continue to strengthen her star power until the night she experiences the final test...