Cross Mountains and Rivers from the Beginning

He was once a young man with great ambitions, but now he just wants to be an idle person, leaving behind his mentor's legacy that "the world will be in chaos." Until that night, a letter and a game of chess dragged him into the center of the whirlpool. This letter revealed the secret of the late emperor's serious illness and the prince's heir apparent, and also triggered a relentless pursuit. The mighty empire fell apart overnight. And he, who originally took over the task of delivering letters by accident, was forced to shoulder the burden of saving the world. He wants to write a new ending for this troubled world.