A tramp roams the streets of Paris, remembering the days when other people still noticed him, before he became homeless and invisible - just a "black hole in the city" to ordinary people. In those distant days, he was the partner in a promising small business. Betty, twelve years younger, loved him with all her heart, admired his vigor, and bore him an adorable little girl called Francine. At 55, he's on the scrap heap and about ready to go under - no one would miss him, anyway. Then, during a scuffle, a dog befriends him and starts to follow him around.