At twelve years old, Mitsuki Kouyama is diagnosed with a rare form of throat cancer, sarcoma. Faced with the option to remove her vocal cords and potentially cure the disease, she refuses, driven by her dream to become a pop singer and honor a promise made to her childhood sweetheart, Eichi Sakurai, who moved to America. As her condition deteriorates, Mitsuki accepts her grim prognosis.
One day, while escaping from her grandmother's house—where music is forbidden—to attend an audition, Mitsuki encounters two shinigami, Takuto Kira and Meroko Yui. Recognizing that she can see them, they inform her that she has only a year left to live. Moved by her circumstances, Takuto offers Mitsuki a way to pursue her dreams by transforming her into a healthy sixteen-year-old. With renewed hope, she successfully joins Seed Records and debuts under the stage name Full Moon, determined to fulfill her musical aspirations before her time runs out.
Included one-shot: Volume 2: Full Moon wo Sagashite