In the dazzling women’s sanctuary known as the Moonlight Imperial Harem, Rin-ka Yu, a kindhearted girl beloved in the distant province of Unkei for her knowledge of medicinal herbs, receives a divine oracle declaring that she must enter the palace as one of the emperor’s consorts. Amid whispers of pity toward the girl destined to marry the cold-hearted Emperor Shiyo — the man who overthrew his own father — Rin-ka carries a secret determination within her heart. Her true goal is not to win the emperor’s affection, but to uncover the truth behind her greatest secret: the mysterious power that causes her to transform into a tiger. However, soon after entering the harem, her secret is discovered by Shiyo himself… A sleepless emperor and a princess cursed with the spirit of a tiger — their fates intertwine in this grand romance set within a mystical imperial court.