Deng Gui Chan, a strong businesswoman known as "Seventh Master", is competitive and often pushes herself off the cliff and puts herself to death. Chai Shi Qi is a business wizard. They interact with each other. Taking advantage of each other, colluding with each other, falling in love and killing each other, and in the end they are willing to risk everything for each other, including their lives.

Guangzhou is in a state of political turmoil in the 1930s. Gangsters are on a rampage and opium trading becomes rampant. As they watch the illicit profits from opium trading escalate, the government forms the Anti-Smoking Bureau under the guise of suppressing opium, but the bureau is under the influence of Cheng Long-kwan, the gang's kingpin. His eldest daughter Cheng Kau-mui  who is an unscrupulous person soon returns from Shanghai to reap the rewards. Mui meticulously plans her every move. On the other hand, Lau Sing  is the leader of the Criminal Investigation Team. He has worked hard all his life to ensure an easy trail for his family, especially for his bed-ridden younger sister Lau Ching. Despite his hot temper, he values friendship and brotherhood more than anything else. Once, he almost sacrificed his life to help his timid teammate, Pai Kuat. Meanwhile, the Japanese army invades China and Canton falls into the hands of the Japanese. Mui enters the darkest time in her life when her aunt Cheng Long-hei frames her.

Set in Eastern China in the mid-19th century Qing Dynasty, Rosy Business tells a story of the mercantile Chiang family and the ambition and jealousy surrounding the issue of who was to own the family business when Chiang Kiu dies. The story surrounds the life of Hong Po-kei, who marries into the Chiang family as Chiang Kiu's fourth wife. She gains ownership of Hing Fung Nin, the family rice shop, and guides the ambitious coolie Chai Kau to rise in the social status ladder.