Her name is Siella Remour, the daughter of an impoverished nobleman whose destiny is to marry successfully to help the family. But Ciella wants to change her destiny. Obsessed with wanting to be needed by society, she dreams of helping the magical police with the investigation of the case of a maniac nicknamed Ace. And when Ciella's lover becomes the victim, desire turns into obsession. She will do anything to achieve the goal. She will run away from home, become a mute servant of the one who is in charge of the Ace's case, even fake her own death! She will find the Ace. But won't the price be too high?