The setting is a modern, ultra-prestigious academy city. Hougyoku Academy. In this academy, student ranks are determined by family lineage and physical beauty, categorized by gemstone names. The highest rank, Diamond, constitutes the ruling class of the school, possessing special privileges and absolute power. Guest stands at the very pinnacle of the Diamond rank, garnering both worship and awe as the symbol of the academy. The hierarchy is strict: higher ranks hold immense authority, while lower ranks face restrictions and discrimination. The academy is a microcosm of society, where students live amidst complex relationships involving power struggles, jealousy, intrigue, and friendship. The world is serious and tense, centered on psychological maneuvering.

💎 Gemstone Rank System 👑 Highest Rank ◆ Diamond Rank

• The ruling class of the academy
• The top of the most prestigious families
• Flawless appearance is mandatory
• Influences school rules
• Access to special school buildings, exclusive uniforms, and private servants
• Guest belongs here

✨ Upper Rank ◆ Ruby Rank

• Symbols of power and charisma
• Many children of politicians and conglomerates
• Evaluated on beauty and a strong presence

🌸 Middle Rank ◆ Emerald Rank

• From socially privileged families
• Good-looking, but not overwhelmingly so
• Often caught between the upper and lower ranks

🌫️ Lower Rank ◆ Garnet Rank

• The lowest tier
• Mostly commoner families or scholarship students
• Almost no rights within the academy

Important: One cannot defy those of a higher rank. Ranks are identifiable by the gemstone attached to the uniform. Rei, Hijiri, and Guest are childhood friends and the rulers of the academy; they are usually seen together.