Denise Lovett, a young and ambitious country girl with only her wits to live on, arrives in a Northern city to work in her uncle Edmund's drapery shop. But she soon discovers that he cannot afford to employ her – his customers have abandoned him for the glamorous department store across the street, The Paradise. Desperate, Denise takes a job in the Paradise's ladieswear department.
Moray, haunted by the rumours surrounding the mysterious death of his wife Helene (of which staff are forbidden to speak), is courting the dazzling and wealthy Lady Katherine Glendenning, whose powerful father Moray needs to charm to secure a loan for his store’s expansion. Katherine is desperate for Moray to propose but, much to her frustration, Moray is committed to his first love: The Paradise.
Ambitious and forward-thinking, Moray plans to expand. Glendenning is sceptical that there’s money in retail, so Moray sets out to impress him with a huge sale. But Dudley, the manager of The Paradise and Moray’s number two, is concerned that Moray’s dreams of expansion could lead them to ruin.
As Denise settles into ladieswear, her spiteful colleague, Clara (herself smitten with Moray) wilfully makes life difficult for her. Meanwhile, the sinister store detective, Jonas Franks, warns Denise not to ask questions about Moray’s wife.
Katherine’s determination to make Moray propose escalate and he loses his temper. But while each of them manipulates the other for their own agenda, they cannot deny the spark of passion between them and Moray allows himself to be seduced. Glendenning warns Moray that if he hurts Katherine he will ruin him.
Working into the night, brimming with ideas, Denise overhears Jonas telling Moray that Dudley, worried about how they will pay their suppliers if the sale falls short, has gone behind his back to the suppliers, promising to return what The Paradise cannot sell. But in revealing a lack of faith in Moray, Dudley has caused suppliers to doubt him, too, and withdraw. In response, Moray offers The Paradise as a guarantee, risking everything.
When Denise sells a dress to Katherine Glendenning, Moray observes her innate gift and his head is turned by her beauty and talent. When he summons her to his office, he tells Denise that he observes something different in her from the other girls.
The grand sale is a big success and Moray secures a personal loan from Lord Glendenning for his expansion. Moray explains to Katherine that they cannot marry, not yet anyway; The Paradise’s success relies heavily on him remaining single.
Katherine's oldest friend, Jocelin, pays a visit to Belville Hall and is soon seduced by The Paradise's merchandise. Because Jocelin is spending money with such exuberance, Moray allows her to have an account, confident that her husband will settle her bill. But Denise notices a note of hysteria in Jocelin and wonders if her actions are masking a disturbance.
Meanwhile, Denise conceives of an exciting marketing campaign to crown a customer "Miss Paradise Pink," yet is reluctant to be credited with her idea. Miss Audrey is flustered when Moray tasks her with leading the promotion. She then turns to Denise to supply her with further ideas.
Jocelin’s slightly hysterical shopping on subsequent visits to The Paradise becomes frantic, and when Sam comes to her rescue, she invites him to Belville Hall to show her thanks. Sam’s kindness prompts Jocelin to reveal her deepest secret: she has left her husband. In the throws of a breakdown and blinded by Sam’s kindness, she kisses him. At that very moment, Katherine and Lord Glendenning return home and witness the kiss. To save face, Jocelin slaps Sam.
With calls for Sam’s dismissal from the outraged Glendenning family, Moray risks his relationship with Katherine in order to uncover the truth. The shop is alive with gossip about Sam, and Denise begs him to tell Moray the truth. But Sam nobly protects Jocelin's secret, working in the delivery yard during the investigation.
Glendenning discovers an extravagant gift and note of thanks that Jocelin intended to give Sam. Now uncertain of her innocence, he still believes the matter is best resolved by Sam's removal. Suffering, Sam confides in Denise, who pleads with him to tell Moray. But he feels sure that a lady like Jocelin will do the right thing.
When rumours about Sam escalate, he seeks out Jocelin, but his pleas fall on deaf ears. Denise informs Dudley and Moray about Jocelin’s secret and destructive state. Moray takes the truth to Katherine, who persuades her friend to retract her accusation. Sam’s reputation and job are restored.
The success of the "Miss Paradise Pink" promotion makes Denise shine in Moray's eyes and he becomes inspired by her quicksilver mind.