Bu Tian Ge (步天歌 Bù Tiān Gē), also known as Song of the Sky Pacers in English, is a manhua by Chinese artist, Xia Da.
The story follows the twins and protagonists, Chen Ating and Qu Chen. By cruel fate, the twins are separated after birth. Qu Chen is taken into the celestial world as a disciple under the immortal Cang Wuzi to train as a cultivator on the celestial mountain Penglai as preparation for the coming Heavenly Calamity. Chen Ating remains in the mortal realm and is adopted as the granddaughter of the lone swordsman named Chen Yansheng. Chen Ating experiences tragedy after her adoptive grandfather is killed by the rogue cultivator, Baili Ji, who takes her as his disciple and forces her upon the path of cultivation, and so, Chen Ating swears to take revenge. Meanwhile, Qu Chen sets out to find his twin sister.