Great Qin Medical Ancestor: in the Beginning, the First Emperor Gave up Alchemy

Modern young man Li Sheng accidentally traveled through the Qin Dynasty and became a down-and-out alchemist who made elixirs for Qin Shihuang. The original master's skills were poor and he failed many times. He had already angered Long Yan, and the beginning was a dead end. In a desperate situation, he accidentally bound to the heaven-defying system, rewriting his destiny and starting a thrilling counterattack for survival!