No one would ever accuse Alfred Hitchcock's "Shadow of a Doubt" of being plausible, but it is framed so distinctively in the Hitchcock style that it plays firmly and never breaks out of the story. Later you question the absurdity of two detectives following a suspect from New York to California, apparently without being sure of how he looks, and hanging around idly outside his residence for weeks while chatting up the suspect's niece; one of them eventually even proposes marriage. Nor are we convinced that the niece, believing her uncle is a killer of old ladies, would allow him to buy her silence by promising to leave town (because his guilt would "destroy her mother").
The town and the Newton family play major roles in the film, and may reveal Hitchcock's own inner feelings. He shot in late 1941 and early1942, at the outset of World War II, at a time when he was unable to visit his dying mother in London because of wartime restrictions. He later credited the friendliness of the town for making this the most pleasant of all his film locations. His emphasis on the comfy Newton home, a chatty neighborhood, a corner cop who knows everyone's name, the nightly meals around a big dining table--all add up to a security that both he and Uncle Charlie were seeking, and Charlie rhapsodizes about the joys of home and family.