The world of blue and darkness. The Dark World and Nine Days in Feng Xiao are both from the TV series The Trial World, which is a costume TV series starring Yang Yang and Zhao Lusi. In the play, Lan Daren's skill is very powerful, but no one can beat him in the play. Nine days' skills are weak, so by contrast, Lan's dark world is even worse. The play tells the story of Feng Lan Xi and Bai Fengxi traveling around the world together.