A first-person internal narrative, the book starts in the early morning and follows all of the day's events straight through. While the day happens in chronological order, the tale is frequently interrupted by flashbacks and remembrances of a difficult past. At several points the text steps away from Willy and assumes the voice of his dead wife Irene. This is the first instance of Swift using many of these techniques in a long novel. Viewed against the early short stories and the later novels the beginning of a writer's stylistic evolution can be seen.
Irene, an assertive and intelligent shrew, marries Willy to avoid the larger problems that her possessive yet callous family presents. Shortly after the marriage she retreats into growing illness, eventually becoming an invalid. In an attempt to buy off Willy's love she buys him a shop on the High Street and makes sure that he is kept busy with running his business. It is only out of an uncharacteristic (and unexpected) sense of duty that she grants Willy a child, Dorothy. Dorry can sense that her mother resents her and her father is unable to understand her emotions and intelligence, differences that she is never able to reconcile and will cause her to leave home and abandon her father in his old age.
The Sweet Shop Owner is also the story of a small London suburb as it grows into modern times, experiencing growing pains along the way. The High Street shops evolve from family operations into corporate enterprises and along the way lose a great deal of their humanity. The evolution of the street is depicted especially well by the real estate office of Hancock, Joyce, and Jones. As the patriarchal owner of the store grows too old to run it (and eventually dies) the names on the door shift and Hancock attempts to expand it into a chain of realty stores. The only thing that remains constant through all of the change is Willy's devotion to his own store, the only way that he is allowed to demonstrate his love for Irene.
A subplot to the novel involves two of Willy's employees, the jealous middle-aged Mrs. Cooper and the teen-aged Sandra. The two fight for Mr. Chapman's attentions, and represent Swift's ongoing characterization of the gulf that exists between generations. Another major subplot is the all-too-factual World War II. Forming a large part of the backdrop for Willy's flashbacks, it parallels many of the problems that the individuals in the tale must solve.
Willy, paralyzed with the pain of his heart condition, is waiting vainly for Dorry to come see him one last time as the novel ends. "She would come -- she hadn't said she wouldn't ." (p.9) The Sweet Shop Owner offers insight into the lives of ordinary people. Many of Willy's recollections seem mundane, even trivial if taken one at a time. Looked at in the context of the entire work, they form part of an elegant whole.