Big Demon Qi Feng Yin, born out of evil thoughts, is locked in the Panic Mountain Barrier due to his killing of the mortals and immortals a thousand years ago. The small Medicine Spirit Ya Mao, transformed from the herb Huanyangcao, is chased by all sorts of people due to its magic physique and happens to break in the barrier, leading Qi Feng Yin's failure to have a human body and his evil thoughts fly. Since then, the two have had a deep bond and have experienced all kinds of stories together.
