Tim is a child who lost his mother when he was young. After his father remarried, he was often abused by his stepmother, which made his life extremely depressing. He felt happy only when his father accompanied him to the racecourse on Sundays. Unfortunately, his father was killed by a wooden board on a construction site soon, and he lost his only warmth and comfort. From then on, whenever he felt wronged and bored, he would go to the racecourse to relax and relive the happy times with his father. But although little Tim was very miserable, he had a unique smile in the world. Once, Tim came to the racecourse again, where he met a mysterious old man. The old man wanted to exchange Tim's smile with the condition of "making Tim win every bet". Young Tim felt that there were not many things worth laughing about in life, so he agreed to him in a hurry and doubt. From then on, Tim lost his smile, but only exchanged it for huge wealth. Next, the kind-hearted Tim met many friends in a completely subverted life, but he could not share the joy with his friends-he could not laugh. After tasting the pain and bitterness of life without laughter, Tim gradually became mature and strong. Finally, he decided to redeem his smile. With the full help of his friends, after many twists and turns, and after a battle of wits and courage with the mysterious old man, Tim and his friends finally defeated the old man, took back the smile that was betrayed, and lived the smiling life they wanted.