Fiasse is a world‑renowned singer who now serves as the headmistress of a special singing school that hosts a Charity World Tour every year. After her mother’s death, Fiasse inherits a legacy that draws the attention of shady individuals. To protect her, Ellis and two siblings, Kyoya and Miyuki, who are masters of the sword, are brought in. As the World Tour approaches, Ellis, Kyoya, Miyuki, and their allies must defend their childhood friend at all costs.