The strong influence and power of Spanish navy has enabled Spain to become the foremost kingdom in Europe during its Golden Age. But this powerful navy force has always been relying on the Frontera Family, which was traditionally tied to serve the Spanish royal. But this tie was under the threat of being broken when kingdom was under the reign of Philip II. Leon became the new leader of Frontera Family when he was just 12 years old. Although Philip II has shown great respect to his deceased father, the king paid little attention to the “child leader”.

Behind the prosperous human civilization, the dark genus that was supposed to be quietly buried in history — the "beast". But the "warfare" brought by someone changed their destiny. There was no way for humankind to do it in front of Terion, who regained his original power and instinct and became a hunter again. Takuya Shinomiya is an ordinary high school student who attends a private Todo school with Reina who grew up like a brother and sister. However, from the time he was fascinated by the transfer student, Kuji Hinako, his daily life collapsed. The shadow of the terion jumping into the city, Hinako who is chasing the terion. And when Takuya and Reina regain their lost childhood memories, the wheel of fortune begins to turn!

That night, Fujima Yamato got involve in serial murder and almost got killed but she was saved by a transfer student, Shinonome Shizuma with a magic. Yamato had been awake at her house. Yamato offers her some assistance for Shizuma who came here to stop a serial murder that was done by a beast, but he gets rejected by her. However, he doesn't give up. Even though he got rejected and follows her but...

The sixth-grader Reo has to be mature for his age because of his divorced parents. When his father decided to remarry, Reo was sent away to live with his estranged mother who had remarried, too. It turns out the only one who could actually take him in is Reo's older step-brother who he had never met. This will make for an awkward family life? *Note: Includes 2 extra chapters.*