Koki, a tattoo artist, has excellent tattooing and designing technique, but he wasn't interested in people and had a difficult personality. Mia, Koki's only regular customer who had a certain obsession with "pain" stemming from his early life, begged him to tattoo all of his designs on his body. Koki gradually fell for Mia's unhinged and dangerous allure, but his true feelings remained yet to be seen. But what will happen to their faint relationship like a thin spider's thread?