The story begins at an old market with a history that goes back more than two decades. Wu Qishan (Tay Ping Hui), a stallholder selling fruits, is an ordinary “uncle” and a maths whiz. He never makes mistakes in calculating the prices of his fruits and he can solve any mathematical problems. The stallholders in the market nicknamed him “573”. In his spare time, Qishan helps out at his mother’s (Xiang Yun) vegetable stall but she is cold towards him.