Galett Fey Sowauge, fourth princess of the wealthy and technologically advanced Vansable Empire on the Eastern Continent, is dispatched as a sacrificial offering to the demon lord Exoda C. Claw on Shina Dark. This act stems from her empire's belief in false legends depicting Exoda as destructive and lustful, seeking peace through appeasement.

Raised by her father Emperor Galeon Fey Sowauge's adviser, whom she calls "Grandfather," Galett received rigorous training in knightly chivalry and combat. This instilled a profound sense of duty, justice, and considerable swordsmanship skill. Arriving at Shina Dark, she discovers the legends are fabrications; Exoda rules peacefully, showing no interest in destruction or sacrificial maidens.

Exoda bestows upon Galett the title of Green Moon Princess, making her one of the Twin Moon Princesses alongside the Blue Moon Princess, Christina Rey Holden. They serve as symbolic leaders for Shina Dark, an independent nation Exoda establishes for abandoned women unable to return home. Galett actively contributes, notably organizing and leading a protective militia for the island's inhabitants. Her governance duties intensify during Christina's periods of incapacitation due to health issues.

Over time, Galett finds herself drawn to Exoda, influenced by his compassion and dedication to giving the exiled women purpose and safety. This emotional shift creates a complex dynamic with Christina, whom Galett regards as both a close friend and a romantic rival. Galett navigates the tension between her ingrained knightly ideals and the practical necessities of governing a nascent nation, embodying loyalty and adaptability amid political and personal upheaval.