My name is Leon Arnaldo, and I'm a boy who was adopted by a famous female detective. But my life is anything but normal. This young boy's got a secret: I'm a man from the modern world who's found himself in the game "The World of Criminal." For five years, I spent my days adventuring and solving various cases alongside her. But that adventure came to a sudden end when we got some terrible news: the detective had been killed. In the middle of all the craziness and sadness of a story that was getting out of hand, I had a realization—the detective who saved me was actually keeping a secret that could shake the whole world.