Born into a prestigious family yet possessing zero spiritual power, Rin lives a life of constant abuse as the 'Useless Nameless.' Forced to act as a poison taster for her younger half-sister, Hinako, her body is slowly being devoured by curses every day. However, during the Priestess Selection Ceremony, everything changes. One of the supreme gods, 'Seiryu' (The Azure Dragon), chooses Rin—not as a mere priestess, but as his one and only fated partner... his 'Tsugai-sama' (Eternal Mate). A high-tier, cold-hearted god and a persecuted, nameless girl—the curtain rises on a supreme Japanese-style Cinderella tale.