Champion is not a happy boy. He leads a very lonely childhood with his aunt, Madame Souza. Aware of his misery she does everything she can think of to cheer up his life. She buys him a TV, a train set and even a dog, but nothing raises a smile. One day she notices he is cutting out articles on famous cyclists from the newspaper. Inspired she rushes out to buy him his very first tricycle – and is amazed to discover his passion for cycling. This passion becomes the cement for their strange relationship. As he grows up she trains him mercilessly in his chosen sport and eventually enters him for Le Tour de France. During the race, Champion is kidnapped, along with two other cyclists by two sinister-looking men who are driving a phoney official race vehicle. On finding his crippled bicycle by the roadside Madame Souza , with her faithful fat dog, Bruno, sets off on an epic adventure to find her Champion. Their journey takes them across the Atlantic to a vast metropolis called Belleville. There, Champion is imprisoned by his captors – the notorious French Mafia – who are training him to race stationary bicycles for illegal gambling purposes.