This story takes place in ancient Liang, where many locals, upon their deaths, have their bodies inhabited by souls from 2,000 years in the future, transforming into time travelers. These time travelers bring advanced experiences and knowledge to Liang, simultaneously raising suspicions and concerns among the reigning emperor. Amidst the changing tides, a time traveler named Lou Zhu, who advocates for peace, forms a deep bond with Zuo Yunqi, a native member of a prominent family, and attempts to find a path to progress and coexistence for all. However, tensions between the imperial court and radical time travelers escalate rapidly. In an explosive incident, Lou Zhu becomes entangled to prevent mutual destruction but tragically gets buried under a collapsing mountain, and his fate remains uncertain. Half a year passes in the blink of an eye. Seizing the opportunity presented by the major explosion, the emperor orders the eradication of all time travelers, while a radical time traveler organization called the "Pioneers," led by Jiao Jiaoran, seeks to use the upheaval to overthrow the imperial authority and gain an advantage in warfare through the use of modern weaponry. Both sides share a common focus—the legendary Lou Zhu, who is said to be recovering from injuries in the martial arts community.

Failed kamikaze pilot Ken Asuka becomes a rough, tough hooligan who settles all of his problems with karate, until he learns about the legendary swordsman Musashi Miyamoto in the novels of Eiji Yoshikawa. Resolving to live his life like Musashi, he begins to take karate more seriously. Based on a manga by Ikki Kajiwara and Jiro Tsunoda, itself inspired by the real life of Yasunobu Oyama, the founder of the "hard-knock" Kyokushin Karate school.