Oda Teruasa, a gifted high school senior who is the heir of Japan’s wealthy trading company Oda Group, lost everything 13 years ago when his father was murdered by a mysterious organization. The culprit was, in fact, after a weathered key which was in Seiji’s possession. Whoever acquires this key will allegedly see their fortune rise with the number of keys they collect, and with 99 keys, one can gain control over everything in this world. Entrusted with this key by his father just before the fatal incident, Teruasa managed to escape overseas, and since then, he has traveled the world, accumulating knowledge and experiences. Returning to Japan after 13 years to avenge his father, Teruasa finds himself entangled in the “Akuma Game”, a life-threatening battle of wits against rivals aiming for the demonic key.