The Stranger was the first film directed by Orson Welles following his Rio documentary It's All True. His work on It's All True earned Welles an unfair reputation: that he was profligate and extravagant. The Stranger was a conscious (and successful) attempt to prove otherwise - to show that he could make a regular, popular film within the studio system, on-budget and on-schedule.
In the film, Welles plays a Nazi war criminal (the architect of the Holocaust, no less) who has changed his identity and escaped to a small American town. He marries a judge's daughter, played by Loretta Young, to keep up appearances. Edward G Robinson plays a detective attempting to track him down.
A similar situation occurs in Alfred Hitchcock's Notorious, made in the same year, with the major difference being the role of the Nazi's wife: Loretta Young's extremely naive character is very different from the Ingrid Bergman role in Notorious. A more general comparison could be made with Hitchcock's Shadow Of A Doubt, in which a killer seeks refuge in a small American town; in that film, it is the killer's sister who is (initially) as naively unsuspecting as Young is in The Stranger. Welles's line about watching people from the clock tower "like God, looking at little ants" anticipates his role in The Third Man, when he looks down from the ferris wheel at the "dots" below.
The Stranger is a less personal project than Welles's other films, though it does include numerous high-angle and low-angle shots which add visual interest. The dark lighting and heavy shadows are not only typical of early Welles but also typical of the period, as by this point film noir had caught up with Welles's eccentric cinematography. (Welles later directed the final film in the classic noir cycle, Touch Of Evil.)