When Gu Yunzheng, an associate professor of neurosurgery, goes on a medical aid mission in Lacaya, he meets Su Wei'an, a"deserter" who has abandoned her medical career to become a businessperson. From bickering all the time to falling in love with each other, he gradually discovers that all her abnormal behavior is caused by a genetic disease called Huntington's disease. The love for his beloved one makes him empathize with the sadness and despair of this incurable disease faced by 30,000 patients and their families across the country. Finally, Gu Yunzheng decides to give up his promising career and devote his life to the research of curing this rare disease, fighting alongside his lover to carve light out of the darkness.