Red lightning in a thunderstorm struck an autistic terminally ill girl named Jin Chiyu and her pet cat Xiaobai, causing their souls to exchange.
In reality, through Jin Chiyu's terminally ill body, Mao Xiaobai appreciates the warmth and coldness of the world in the countdown to life, and steps out of autism.
In the cat world, Jin Chiyu used human wisdom through Mao Xiaobai's king's body to help the cat world win the war with the dragons, and finally succeeded in opening the sealed door to heaven and earth.
In the end, both of them adapted to each other's world and each gained their own love. However, a thunderstorm and the red lightning struck again. Will they choose to exchange souls again and return to each other's world?
Purpose: Jin Chiyu, a terminally ill autistic girl, exchanges souls with pet cat Xiaobai. The girl becomes a king in the cat world, and uses compassion to resolve the thousand-year war between the cat world and the dragon world over the gates of heaven and hell. In reality, Mao Xiaobai appreciates the cold, warm, black and white of the world through Jin Chiyu's countdown body.