Welchester professor, Kensuto Kanzaki, is murdered at his home, under the cover of a stormy night. Left upon his desk was a cryptic letter he was writing - almost as if he knew he was being hunted and wished to leave behind a clue. His son, Kounosuke, was taken into legal guardianship by Ken's friend and colleague, Professor Hayama Ryu.
     One year later, the letter makes it's way back into Dr. Ryu's hands, and he begins his own investigation - following the clues his late friend left behind. When it turns out the top secret Rukian sect, Overture, was also trying to learn more about the notes Kensuto left behind. 
     The overlapping interests of both sides sets in motion a race against time to locate the artifact that Kensuto was researching and pursuing. 
     Meanwhile, Hoshima Sayuri and his childhood friend, Saki Hatatata, receive their acceptance letters to Welchester Academy. Little did they know that their class was going to be under the tutelage of Dr. Ryu, and that they would be pulled into the professor's underground operation to finish the search that Kensuto began.