When Jack Gay, a debonair man about town, married Stella Nagg, he also married her family. Arabella, his domineering mother-in-law, arrives for a visit, accompianied by her henpecked husband Noah, and stage-struck daughter Ima. Willie Nagg, brother of Stella and Ima, is secretly married to Stella's maid, Sally. They have kept their marriage a secret owing to lack of money, but Willie is taking part in a boxing contest for which he will get £200, and he is then going to tell his family the truth. Their small baby has been cared for by Sally's Cousin Tillie, but as she has gone on holiday they have had to look after the infant themselves and have temporarily concealed it in the summer house. Jack has bought Stella a piano as a surprise, and awaiting an auspicious occasion to present it, has had it taken to the summer house. Unfortunately, they have a slight tiff, and in an endeavour to bring about a reconcilliation Jack writes Stella a note, telling her to look in the summer house. She does, and finds the baby, immediately concluding that Jack is the father. There are many amusing situations with everyone working at cross purposes before the matrimonial mix-up is eventually sorted out.