The owner of 'Witches' Nails', Song Hye-jin. Running a 1:1 reservation shop, she finds herself concerned about her weekly customer, Kim Woo-ri. With her beautiful manners and delicate hands that seem like they wouldn't tire you out even after a whole day of touching, Hye-jin gradually feels attracted to 'Sister Woo', but she is careful not to cross the line beyond the relationship with a customer. One day, Hye-jin learns that Woo is a well-known skilled skincare therapist in the area, and Woo invites Hye-jin to her massage shop, saying, 'I'll give you a service, so just come once...'.