Mary, 8, is a fat girl who lives in Melbourne, Australia. She likes cartoon "Noblitt", sweetened condensed milk and chocolate. Mary's mother is an alcoholic, while her father who works in a tea packaging factory only likes to make bird specimens on weekdays. Lonely Mary has no friends. One day, she tore a corner from the telephone book of the post office and wrote a letter to Mr Marx who lives in new york. She wanted to ask him some strange questions, but she received an unexpected reply.

Marx, 44, is an obese Jew with Asperger's syndrome (an autism) and lives in noisy new york. He also happens to like watching "Noblitt" cartoons and eating chocolate. Under the pressure of life, he always feels that he is out of place in this world and very lonely. One day, he received a letter from Mary, a strange little girl from Australia, with a cherry chocolate bar that he liked very much. After Marx wrote back, they became pen pals.