Down-on-his-luck young man Gu Changfeng unexpectedly discovers that he has a three-year-old daughter, Gu Niannian. He enters into a contractual flash marriage with Leng Chuyue, a cold and aloof female CEO, and begins living under the same roof with her. Although he appears to be living off someone else's generosity, he actually awakens the Billionaire Dad System. Whenever his daughter is happy, he can unlock extraordinary skills such as cooking, combat, hacking, and racing. Transforming into an all-capable dad, Gu Changfeng protects his daughter while repeatedly taking on the villain Wang Ji and revealing his astonishing abilities. Under the same roof, this pretend married couple gradually untangles the knots of their past through everyday family life and dangerous trials. Leng Chuyue is repeatedly astonished by Gu Changfeng's hidden identities and abilities, and the two slowly move from a contractual relationship toward a sweet romance in which they wholeheartedly choose each other.