Celia (Hy Hazel), an attractive but hard-up actress, has a passion for expensive hats. She is offered the chance to earn some money to buy one by her friend Larry who runs a detective agency. His clients Mr and Mrs Haldane were concerned for their rich Aunt Nora, having had no contact from her. The Haldanes had visited Nora's country house only to be told by her new, younger husband Lester (John Bailey) that she was ill and did not wish to see them. Celia reluctantly agrees to infiltrate the house by posing as a replacement housekeeper.
'Celia' was one of the earliest films made by Hammer Film Productions on behalf of Exclusive Films. This small company ran on a shoestring and started out by making films of successful BBC radio programmes such as the legendary Dick Barton. It is hard to imagine a more budget budget-film than this one. All the interior shots were made entirely within a country mansion in Cookham, Berkshire, specially hired by the company for around £25 a week (1949 prices) with almost every room as well as gardens being used for shooting – and it shows. In fact, the star Hy Hazell happily lived in the mansion during shooting and so saved hotel costs. The entire film cost about £13,000. (The same mansion was used in the making of 'Doctor Morelle – The Case of the Missing Heiress' – released in June 1949). Miss Hazel gives an enjoyable performance opposite the creepy John Bailey.