Designer Katherine suffers harsh criticism from her boss Sebastian at work, and is also secretly framed by her colleague Beatrice. One night, Katherine makes an angry wish, which unexpectedly curses the arrogant CEO Sebastian to turn into a black cat every night. On a rainy night, the helpless black cat is picked up by the unaware Katherine and taken back to her shabby apartment.
By day, he is her stern boss; by night, he becomes a cat. Through their time together, Sebastian witnesses Katherine’s kindness and talent, and learns about her heavy burden of covering her mother’s medical bills. He secretly helps her clear her name at work while hiding his shapeshifting secret. As Beatrice keeps plotting revenge, Sebastian’s secret is nearly exposed. In the end, Katherine’s whole‑hearted acceptance breaks the curse. The two resolve all misunderstandings and find love.
