Those with blood on their blades do not cross the Lower Yangtze.

"Those with blood on their blades do not cross the Lower Yangtze." No So-ha is the sole heir to the Nine Flow Swordsmanship, a martial art renowned as unbeatable, yet he lives a quiet life supported by three lines of work: fishing, ferrying passengers across the Lower Yangtze, and serving as a hired killer for those who have suffered injustice. Though he works hard to avoid becoming entangled in the feuds between martial arts sects, he ultimately accepts the most perilous commission of his career—escorting a young girl to safety in Korea. She carries the missing portion of the Sun Gun Gyung, a 1,500-year-old medical treatise originally written for Emperor Qin Shi Huang and regarded as the key to attaining immortality. This Korean xianxia webtoon follows the adventures of a blade-for-hire in Yuan-dynasty China.