The town of Saiwei is the third largest town in the empire. After the death of Duke Vival, the nobleman in the town, his two daughters led two knights to manage the light and darkness of the entire town respectively.
Helen Vival, as the elder sister, owns the Knights of Light and supports the daily life of Savvy Town; while the younger sister, Sofia Vival, leads the Knights of Darkness and monitors everything in the darkness.
At a human auction, Sophia rescued a deceived teenager who claimed to be a knight "looking for a master who swore allegiance".
A sister who is gentle on the surface but sinister on the inside
A sister with a bad attitude and a good nature
Annoying and narcissistic psychotic knight
This is how the story begins...