The small family business of the title, apparently the Ayres and Grace furniture business, is finally revealed as something less upright. Alan Ayckbourn’s play concerns the transition in management from the founder/owner, Ken, to his son-in-law Jack. The playwright contrasts the ideas of such businesses as the backbone of lower-middle-class English society with the increasing, late 20th-century corruption and moral decay.
The setting if Jack and Poppy’s home, where she is throwing him a surprise party in honor of his taking the firm’s helm. Even as Jack is declaiming about honesty and rectitude, a private detective arrives to accuse his daughter of minor shoplifting. When Benedict, the detective, tries to blackmail Jack into giving him a job, Jack refuses. This incident opens the door to a discussion among the characters, including Poppy and their other daughter, Tina, about morality.
Jack’s attitude changes, however, when he needs someone to investigate piracy, as the rival Rivetti firm seems to be copying their furniture designs. Setting his moral misgivings aside, he decides he does need Benedict, and hires him to find out if one of his own employees is leaking the information. When it seems that his own brother is the leak, Jack learns that his sister-in-law has been sleeping with the Rivetti brothers.
Ultimately, it turns out that not only is the brother selling their secrets to the rivals, but other family members are involved, trying to generate funds for their various schemes and plans. The whole affair snowballs as Benedict increases his blackmail demands. The play turns unexpectedly much darker when the other family members decide to stop him by having him murdered. Before the murder plot advances further, however, three of the family’s women accidentally kill him.
As the play closes with another family party, the dark turn becomes more pronounced. Jack, abandoning his principles entirely, agrees to pay the Rivettis to get rid of the body—their price is using the furniture business to cover their drug sales. In a final twist, it is revealed that his daughter, Samantha, is one of their drug customers.