In 1938, Mme. Alice (Hunt), chief designer of a famous London fashion house, has lost her touch. Where once she was the most sought after designer in the city, now her creations seem locked in the past and clients are looking elsewhere for modern fashions. She is persuaded by her senior assistant Martha (Hylton) that she needs a long holiday to recapture her creative inspiration. Once Mme. Alice has departed the fiercely ambitious Martha, who has been biding her time for several years, launches a coup, designing and presenting a range of up-to-the-minute garments which are a huge success with the fashion media and bring clients flocking back to the salon. The financial backer of the business is delighted with the upturn in profits; Martha is promoted to chief designer and Mme. Upon Alice's return, whilst retaining her composure, she refuses to countenance the Salon's "Vulgar" new look, prophesies Marthas's doom, and walks out, parting forever from the fashion world.
Over the course of the next decade Martha, with the help of Alison (Pavlow), a talented girl she took on straight out of school, restores the house to its pre-eminent position in the London fashion world. She becomes so driven that she starts not to care whom she treads on in her quest to be the best in the business. Over the years while her professional career goes from strength to strength, she neglects friends, treats associates badly and makes business enemies.
By the start of the 1950's Martha too seems to have had her day; appreciation for her designs tapers off, after a failed love affair with a deceiving lothatio, and her reputation falls. Those she has alienated on the way up are only too happy to watch her on the way down. Meanwhile, Alison, having initially declined to return after finding great success in America, eventually decides to return after all, prompted more by loyalty to one whom she loves at the company than any sentimentality for Martha. Her own designs are acclaimed innovative and contemporary by all. Now, it's Alison who's 'in', and Martha who's 'out': the cycle may begin again.