As Beijing is the world's first city to host both the Summer and Winter Olympics, Ren Chongrong, the documentary's chief director, recalls that she was inspired and intrigued to revisit those who had worked on the 2008 Beijing Summer Olympics and have been devoted to the Winter Games. In a very real sense, they are "dual Olympians".

The first person featured in the documentary is Li Jiulin, the chief engineer responsible for the construction of the National Speed Skating Oval, or the "Ice Ribbon", and the Beijing National Stadium, also known as the Bird's Nest.

Between the ages of 35 and 40, Li pulled out all the stops to work on the construction of the Bird's Nest. Now turning 50, the veteran engineer returned to his "familiar zone "alongside colleagues, tackling the many technical difficulties in building the Ice Ribbon, which boasts a saddle-shaped roof made of steel cables spanning a total of 20,410 meters-the largest of its kind in the world.

With cutting-edge technology, the roof consumes one fourth as much steel as a normal roof built via traditional methods, embodying China's effort to deliver its promise of hosting a green Winter Olympics, the documentary says.

Ren was full of praise.