Suiling, who holds the position of 'Shito' (Palace Lamplighter) in the Inner Palace, has a secret motive. She is searching for her former fiancé—the man who drove her older sister to her death years ago. Having heard rumors that the man is now a eunuch within the palace, Suiling managed to slip inside. However, she has been unable to find any further leads and passes her days in frustrated restlessness. One day, an incident occurs where Suiling utilizes the herbal knowledge she gained in her home village. This unexpected display of skill leads to a deep involvement with a beautiful eunuch named Kouryuu...?! The long-awaited manga adaptation of this Inner Palace mystery follows a girl's pursuit of the truth behind her sister's death!