Kam Yuk (Amy Kwok), who is rescued by the kindly owner of a soya sauce factory (Felix Lok) from being sold into a brothel as a child. She becomes the child bride of Tau (Bosco Wong), who's the son of the factory owner. She's little more than a maid to the child, as she literally raises him. Tau is a spoilt brat and so Kam Yuk persuades an idealistic teacher, Mak Sau Sing (Evergreen Mak) to teach him, but Tau tricks Mak into selling himself to the family to pay off the debt of his friend, Sor Koo (Wayne Lai).
When Mak finds out from his mother that his father was killed by Tau's father, he and Sor Koo cause mischief in the household and eventually trick Tau into handing over the family's business.
However, both Tau and Mak have a common enemy, Cheng Sin (Power Chan), who returns to town after being chased out by the family earlier. He's taken up with the soya sauce factory's rival, Ding Fung, to force Mak out of business.