Cinnamon, the prince of the Einsphener Kingdom, loses his blood family in the midst of a rebellion by one of the kingdom's retainers, Cavity. Since then, he lives as the adopted son under the wings of Fredo, a loyal Einsphener knight. One day, the Fredo family is killed, and Cinnamon's younger sister disappears. Cinnamon begins the journey of seeking vengeance in search of clues of his missing sister. Will Cinnamon succeed in exacting revenge against Cavity? And how will he deal with Shot's revealed plot?