A woman who can't trust people because of her ability to hear lies and a mystic composer who hid his indescribable identity, become involved in each other's lives to uncover the truth.

A boy falls to his death at school, but Ok Chanmi does not believe that her twin brother, Park Wonseok, committed suicide. Chanmi transfers to her brother's school, Yongtan High, and meets Ji Sooheon, who witnessed her brother's death.

Adapted from the webtoon series "Welcome", this TV series tells the story of graphic designer Kim Sol Ah who brings home a cat, unaware that the animal can turn into a human being.