In a modern study, a three-year-old calico cat named Shirley is accidentally sucked into the mysterious old book The Cat Chronicles. She transmigrates through time to a world resembling an ancient dynasty, only to discover that she has become a young woman of about twenty. She retains her feline traits but now has a human body. In a ruined temple on a rainy night, she encounters Song Zhen, a young man who is badly wounded and being pursued.
Song Zhen has a tragic past. He was born a prince, but twenty-three years ago, just after his birth, Queen Zhao Fengyi switched him with a dead civet cat. His real mother, Lady Li, was falsely accused of giving birth to a monster and banished to the cold palace. Song Zhen himself was rescued by a loyal servant and grew up in hiding under an assumed name. Shirley saves Song Zhen using her feline instincts. Though she cannot speak at first and behaves strangely, the two gradually build trust. Song Zhen names her Shen Li and teaches her how to live as a human, while Shirley honestly reveals that she was once a cat's soul.
After briefly settling into life in the border town of Qingshi, the two receive a secret letter from Song Zhen's adoptive father, Chen Tuo. Learning that undercurrents are stirring in the palace, Song Zhen decides to go to the capital and investigate the truth. Along the way, Song Zhen tells Shirley the full story of the palace intrigue from that year.
How will they get through the crisis together?