Meet Eric Nazonokazoku and his twin brother, Caleb. They are descendants to a long line of Japanese billionaires and must uphold their families honor, yada yada yada. At least what their high expecting parents say. But no one knows how exactly the Nazonokazokus got so rich. After a mysterious murder of an old family business partner, Mr. Mikkokusha, the boys start to wonder if the reason their family is so rich is a dangerous secret. They find some mysterious letter from unknown person offering the Emperor advice during WWII. Meanwhile, the boys are also receiving mysterious letters from a person calling them self the Mesuraion, or Lioness urging them give up or else. Will Eric and Caleb be able to solve the mysteries of Mr. Mikkokusha, their family wealth and the identity of the Lioness or die trying.