2021 is a critical period for global energy transformation. As one of the main energy sources of the modern clean energy system in China, natural gas has steadily increased its proportion in primary energy consumption structure, and its difficult journey of construction, struggle and development is enough to be remembered by the times. Our crew visited the natural gas production centers, mainly the Changqing Oilfield, to trace the footsteps of PetroChina's builders in the Tarim, Qaidam, Shanxi-Ganling and Sichuan basins of western China. How to overcome the unfavorable terrain conditions to achieve the west-east gas transmission? How to explore and develop deep-seated oil and gas resources? How to use unconventional oil and gas development technology to break through the restricted areas of efficiency exploration? The programme introduces the clean energy revolution in China since the beginning of the 1990s, generations of people have been seeking to bring China's natural gas industry from a regional to a national energy technology pioneering path, towards a cleaner and more flexible energy economic structure, witnessing a new era of China's energy development.