Nora, the second princess of Lybra, sets out on a perilous task, taking up the guise of an alias. Her objective is to monitor her younger sister, who has wedded the crown prince of Wahnrein, by infiltrating the Dragon Knight Order of the neighboring kingdom. But matters take a turn for the worse when the commander of the Order, Harvey, familiarly referred to as "Dragon Slayer," exposes her true identity. Tensions heighten further as she enters into a pact with a dragon named "Aksel."