In the early 19th century, Choi Ji-on, the daughter of a fallen yangban family living in the northwest of Joseon, finds her life taking a thorny path following her father's death. To support her reckless brother and her ailing mother, Ji-on barely manages to make a living through day labor. One winter day, during a severe drought, she forms a bond with a snow leopard (설표) after removing a piece of metal lodged in its body on a high mountain. "...Let's call it 'First Snow' (초설). That's your name." The snow leopard is not just an ordinary animal; it is a spirit that can transform into a human. As Ji-on names the snow leopard, which has taken on a female form, and brings it home to live with her, she gradually opens her heart to it. Thus, the spirit and the human become friends who rely on each other and share their feelings, and as time passes, romantic feelings begin to blossom between them. In a chaotic world, the precarious romance between the snow leopard and Ji-on begins. Will the world truly protect their love?