Cheon Sang-hyuk has been trapped on earth for 500 years and has lived as ‘Cupid', a matchmaker of humans. Oh Baek-ryeon, an ethereal beauty who committed a great sin in her past life, is doomed to fail every romantic relationship in this lifetime. Just when she is about to give up in love, her fairy Cupid appears in front of her.

Baek-ryeon feels a weird sense of familiarity upon encountering Cheon Sang-hyuk. He secretly watches her wondering why she doesn't have the red thread of fate unlike the other humans. Meanwhile, the night before the snowstorm, a woman gets kidnapped in a public parking lot in Mt. Inwang, and the witnesses of the incident are found dead one by one.

Baek-ryeon expects Sang-hyuk, who heroically saved her from her stalker, to be the man of her destiny, but he draws the line that he does not want to be in a relationship with a human. Meanwhile, Sang-hyuk and Jae-hee run into each other at Baek-ryeon's animal hospital. How were they related to each other in their past lives?