A jumpy home movie shows a six-year-old boy learning to ride his first bicycle with help from his father. The narrator tells us that with each moment, each new experience stimulates growing networks of cells in our brains. "We used to think these changes happened only in childhood, but now we know that our brains never stop developing — they keep wiring and rewiring themselves with every experience and every challenge." After several initial failed attempts — and even crashes — the boy begins to show improvement and confidence. Finally, he is riding alone in a seaside park, amazed at his own accomplishment.
Cut to a spectacular full-screen aerial shot descending the steep eastern escarpment of the Col d'Aubisque in Southern France. As the camera drops down the mountainside, we discover a ribbon of cyclists and vehicles streaming down a narrow, twisting, corniche road. This, says the narrator, is the legendary Tour de France – a 3,400-km, three-week bicycle race that has been called the world's most grueling sports event, and the ultimate test of the human brain.
Australian pro cyclist Baden Cooke and his French teammate Jimmy Caspar are two of the 200 riders competing in the legendary race. Just to finish in Paris, they will need to avoid danger, stave off crushing pain and fatigue, control their emotions, seize fleeting moments of opportunity, and stay highly motivated. It's the brain that controls all of this.
As the tightly-packed peloton speeds towards the first sprint finish of the Tour, the sudden crash of one rider sets off a horrific chain reaction, and nearly 100 riders are taken down. Jimmy Casper is one of the most severely injured. To everyone's astonishment, he opts to continue in the race for as long as he can. Meanwhile, Baden, one of the few unaffected by the crash, manages to win his first ever stage victory, thus becoming one of the favorites to win the coveted sprinter's green jersey.
As the race unfolds, the destinies of Baden and Jimmy diverge. Jimmy desperately wants to help his team by remaining in the race, while Baden becomes the unexpected team leader. As the race crosses the Alps and the Pyrenees, the film combines spectacular live-action footage with cutting-edge computer graphics and medical imagery to demonstrate how each brain responds to experience and challenge in ways we're only just beginning to understand.
"Our goals may not be those of pro athletes,” says the narrator as the remaining riders reach Paris at the end of the punishing three weeks, "but we're all wiring ourselves to win. Any activity that challenges us, and gives us a sense of purpose, will nourish and strengthen our brains."
The film ends as it began, with the home movie of the 6-year-old boy triumphantly riding his two-wheeler on his own. "We fall, we get up, we learn," says the narrator, "Powered by the human brain, there is no end to what we may achieve."