Rebellious wealthy young master Lu Xiao is sent up the mountain by his mother to become an apprentice to a money-loving Taoist priest, where he unexpectedly meets the cold maiden Su Yue and comes to recognize her as his senior martial sister. Under Su Yue's discipline, he gradually learns medical skills, and their relationship shifts from being at loggerheads to growing close. After Lu Xiao descends the mountain, his maternal grandmother falls critically ill; defying the master's command, Su Yue saves her using the 'Nine Returning Needles', becoming famous in a single battle. Afterwards, the two venture into the city to search for Su Yue's life background, making the acquaintance of various figures in the medical world, repeatedly solving difficult problems with Su Yue's needle techniques, and Lu Xiao even builds a medical world support group. Ultimately, her background is unveiled: Su Yue's biological parents are the grand-disciples of a mysterious divine doctor.