Tianfu refers to the Taoist gate suspended in the air; the underground palace refers to the Taoist gate hidden in the earth. There are different Taoist sects but the same sect, but what is Tao? Tao is all things, and all things are Tao. People who practice Taoism use the Qi of the Five Elements to open up the meridians, temper the bones and refine the body, and even become immortals. At the end of the dynasty, all parties are ready to take action; the two parties in Tianfu and underground palace are competing with each other, and undercurrents are surging. In troubled times, when heaven and earth are fighting, you are the only light that saves me.