Harold Hobbs doesn't much like that his lazy, sponging and unemployed brother-in-law Claude and his mother-in-law live with him and his wife, Hortense, especially as the in-laws seem to rule the roost ever since they moved in. To get his in-laws out of the house, Harold has regularly left a bottle of booze for Claude to be able to entertain prospective employers. When Harold learns that on all the other occasions the employers have not showed (he assumes there probably were no prospective employers) leaving Claude to consume the booze on his own, he decides to show Claude a lesson by spiking the bottle with castor oil. Complications ensue when Joe, Harold's friend, encourages him to skip work to attend the prize fight. What Joe doesn't tell Harold is that he tells his boss that Harold needs the day off to attend to the sudden death of his brother-in-law.
