The story takes place at the end of the Warring States Period. Jing Ke entrusted his son Jing Tianming (played by Jiang Jinfu) to Gai Nie (played by Lu Yi), the world's number one swordsman, hoping that the latter could protect his son from the cruel hands of Qin Shihuang. Gai Nie fled with Jing Tianming, and on the way he defeated the three hundred cavalry sent by Qin Shihuang. So, Prime Minister Li Si came out, and rumors bewitched Gai Nie's fellow student Wei Zhuang (played by Sun Yizhou), hoping to get rid of Gai Nie with Wei Zhuang's hands. Along the way, Gai Nie and Jing Tianming met anti-Qin talents such as Xiang Shaoyu (played by Qin Junjie) and Gao Yue (played by Hu Bingqing), and the group finally came to the Mohist Machinery City, which was their last fortress. Soon, Wei Zhuang came with a large number of people, and he even found the Mohist's mortal enemy Gong Shuchou, wanting to take down the machinery city in one fell swoop. Facing the enemy's fierce attack, can Gai Nie and others win the final victory?