Series One

Beatrice (30, known as Bea) and Evangeline (18, known as Evie) Eliott are left orphans by the sudden death of their tyrannical father, Henry Eliott. Left almost destitute and without any education, the sisters are forced to sell the family home to cover their father's debts. To earn money, they make use of their passion for dressmaking and Bea gets a job as secretary at a local photography studio run by Jack Maddox. Jack and his sister Penelope become firm friends of the sisters and Jack provides them with the funds to open their own London based dressmaking business "The House of Eliott". Through their relationship with Penelope Maddox, the sisters meet the loyal and hardworking seamstress Tilly Watkins whom they employ. A consistent theme throughout the series is the struggle of women in the 1920s to live fulfilling and independent lives—for some the struggle is simply to survive. Not only does Henry Eliott leave his daughters penniless and uneducated, but their cousin Arthur, who is executor of their father's estate, and Evie's legal guardian, keeps a rightful inheritance from the girls "for their own good". After Arthur's arrest and imprisonment for involvement in drug smuggling, he emigrates to Boston, USA, releasing a large amount of cash owed to the sisters from their father's estate. This allows Beatrice and Evie to expand the business and, by the end of series one, with the help of Evie's godfather, successful businessman Sir Desmond Gillespie, the future looks good. Evie celebrates her twenty-first birthday and is made a partner in the firm. The House of Eliott releases its first independent fashion collection and is creating exclusive designs for the aristocracy.

Series Two

Spring 1924: the Eliott sisters have employed Florence Ranby, a dour Victorian, as head of the workroom. Beatrice and Evie are invited to Paris by fashion designer Gilles Caragnac, who offers them a 5-year contract as designers for his label. While there, Bea marries her former employer and friend Jack Maddox, and they move back to London, leaving Evie alone in Paris to work at the fashion house "Maison Gilles". After a year and an affair with Gilles Caragnac, a newly-glamorous and grown-up Evie returns as a designer for House of Eliott. Jack's movie director career is on the rise. At a showing of one of Jack's films, Evie meets Lord Alexander Montford, a married member of Parliament, with whom she begins an affair, causing complications throughout the series. Jack and Beatrice separate, unable to agree about having children and the pressure of work. The House of Eliott faces ruin after the suspicious death of Sir Desmond Gillespie causes the firm's financial affairs to be taken over by Ralph Saroyan. The sisters suspect Saroyan of dishonesty and through their contact with Sir Alexander Montford, cause the bank to be officially investigated. It is discovered that Saroyan is defrauding most of the customers of the bank and the Eliott sisters are left with very little of their original savings and investments.

Jack's movie The Strikers is successful and a Hollywood producer offers him work in the U.S. by a Hollywood producer. Jack turns it down to instead work in Berlin. Meanwhile, as the market for couture gowns wanes during the late 1920s Great Depression, Beatrice and Evangeline are offered a tour of America showing their new ready-to-wear designs for Sears and Roebuck. Bea still has feelings for Jack. Back at the fashion house, after a crisis of confidence, Tilly marries Norman Foss, a young chef in a local hotel, and is reinstated as head of the workroom. She announces her pregnancy in the last episode of the series.

Friction exists between Florence Ranby and Tilly. An annoyed Florence walks out of the Eliott workroom and narrowly misses being hit by a car. Tilly has many quarrels with Florence due to her short, sharp manner. Eventually, after Evie allows them to fix a fur collar in Madge's way rather than Florence's, Florence resign and walks out; this time she is fatally struck by a car. At the funeral Mr Ranby, Florence's husband, confronts Madge and Tilly after their apology to him. He then confronts Bea and Evie over Florence's death and how she was treated. He particularly blames Bea and Evie for failing to notice the ongoing conflict and says Florence was loyal and would not hear a word said against them. Later, however, he returns, apologising for his outburst and gives flowers to Madge and Tilly. He mentions he is a tailor. Needing an expert cutter, Bea and Evie consider offering him a job; but they decide against it, concerned that the House's connection to Florence's death would be too difficult for him. They instead hire Charles Quance.

Series Three

The Eliott sisters and employee Madge are wrapping up their evidently successful visit to the United States under the sponsorship of Sears and Roebuck, which wants to carry a line of ready-to-wear designed by the House of Eliott. Still estranged from Jack, Bea has a new beau, debonair Sears executive Donald Bradley, who follows the ladies to England. Bea decides that she still loves Jack and settles down with him just as he is shifting from film direction to investigative journalism. Through Grace Keeble, a talented but unreliable new designer, Evie meets artists Miles Bannister and Daniel Page. Miles is hired to do illustrations for the House of Eliott and later becomes a much needed designer while Daniel is a talented artist who Evie believes only needs a break to be successful. Both men fall for Evie but Daniel wins out. Meanwhile, Madge discovers a new love and it is not her rather gruff husband Jerry. Tilly and her husband Norman struggle to keep their marriage together following the loss of their baby son, William (played by Emily Ryan). By the season end, the House of Eliott has nearly fallen apart, Bea and Jack have a daughter, Lucy (also played by Emily Ryan), Jack wins a seat in the House of Commons, and Evie has married Daniel. Miles' father becomes an investor in the House of Eliott after realising his son is a talented fashion designer. He wants the House of Eliott make Miles a partner and to move away from haute couture and into more profitable ready-to-wear fashions. The final episode ends with a heated confrontation that raises serious questions regarding the House of Eliott's future and the sisters' relationship.

The writers did not anticipate the programme being cancelled at the end of the third series. For this reason, the series ends without a firm conclusion to the storyline.