Time-traveling girl Xie Zhaoyue descends to ancient times carrying the Flying Spirit Cat System. After being reduced to an abandoned daughter of the Minister's Manor, she recognizes the prodigal Yu Wang Xiao Chengyu as her father, with the goal of assisting the crown prince in ascending the throne and returning to the modern era. The father-daughter duo focus on lying flat and slackers, intending to slack off to complete the mission, but repeatedly achieve unexpected merits, sparking endless laughs and leading the emperor to insist on appointing Xiao Chengyu as the heir. To refuse to be emperor, the two cause all sorts of jokes and struggle to cope. In the end, the crown prince successfully takes power, and the country is prosperous and the people are at peace. Xiao Chengyu securely remains in the position of an idle prince, and Xie Zhaoyue also stays in ancient times, living a happy and carefree life together with her old dad and the spirit cat.