Sanmao is a waif in old Shanghai. He has no home, no relatives, no home, no food and clothing. Eat advertising stickers, sleep in garbage trucks, and wear broken sacks to keep out the cold in winter. In order to survive, he sold newspapers, picked up cigarette butts and helped others push rickshaws, but he was always bullied and didn't earn enough money to eat a full meal. Only street children with the same fate care about him and give him warmth.