George Pearson works as a supervisor at Dawson's Underwear Ltd., producing old-fashioned undergarments for women. When the factory overseer, Nelson, is sacked for cheating the firm, George is promoted to take his place. George rushes home to tell his fiancée, Lydia, that his wages have been increased, meaning that they will finally be able to get married. George's unemployed Uncle Arnold, whose chief interest in life is his pigeons, is also impressed. Arnold is invited to stay with the couple in the new house they plan to move into until he finds another job.

George anxiously reveals his wedding plans to his domineering mother. She pretends to have heart trouble to gain sympathy and maintain her hold over George. To Lydia's dismay, George invites her along on his honeymoon, where she causes various difficulties. When the married couple move into their new house, she continues to obstruct their relationship however she can.

A year later, George is sent to London to attend an underwear exhibition, manning the Dawson's stall. Though George sings a song in an attempt to attract customers, it soon becomes apparent that Dawson's underwear is old-fashioned and unpopular. Meanwhile, young women flock to purchase the modern, alluring underwear sold by McKinley's, a rival company, whose stall is fronted by Nelson.

In conjunction with Largos, a confidence trickster, Nelson plots to persuade George to buy the English manufacturing rights to a new yarn that looks good but, he has been told, will not 'make up' properly. George is tricked into signing a contract and promises to pay Nelson £300 for the rights.

Back home, George's mother continues to cause trouble with her unwelcome influence over George's attitudes and opinions. Upon George's return, he guiltily reveals to Lydia that he has spent their entire savings on the new yarn. However, she is sure that he will be able to sell the rights to Dawson's.

George's mother provokes an argument with George and Lydia. Lydia angrily visits the hairdressers and, to upset George and his mother, has her hair dyed blonde. Returning home, she regrets her decision, and hides her hair under a scarf. In another argument, however, her blonde hair is revealed. George and his mother are shocked.

George sends his yarn away to be made into samples of ladies' underwear. Though relations are frosty between them, Lydia visits George at the office to tell him that she has brought the new samples. George arranges for some dummies dressed in the samples to be sent to Mr. Dawson's office. Lydia goes on to say that she is leaving him, because she cannot put up with his mother any more.

Gerald Dawson, overhearing Lydia criticising Dawson's underwear, is impressed by her honesty and asks if she would like to be his assistant. However, George's samples are unpopular with Gerald's traditionalist father, who runs the company, because the material is almost transparent. Lydia and George end up arguing with Gerald's father, old Mr. Dawson, and George resigns from his post. Lydia decides that she will promote the new samples using her own methods, and leaves for London. George, unaware of this, is unable to find a job, and prepares for the bailiffs to come and remove his furniture.

Lydia gatecrashes a London underwear manufacturers' conference, revealingly attired in George's underwear samples. The new yarn causes a sensation. Gerald, spotting her picture in a newspaper, decides to get in touch with her to buy the rights to the yarn.

Meanwhile, as Uncle Arnold's pigeon is preparing to lay an egg in the coop outside George's house, George's furniture is repossessed. Nelson and Largos arrive at George's house; they want to buy the rights to the yarn. Realising that George is unaware of the sensation his wife has caused, they try to persuade George to sell the rights cheaply. Lydia returns just in time, with the Dawsons, and stops George from signing over the rights. There is a bidding war between Nelson and Dawson. George agrees to sell the rights to Dawson's, on condition that he is given a job in the London office, so that he and Lydia can get away from his mother.