Immediately following World War II, ex-Nazi Franz Kindler (Orson Welles) is living under a false identity as a teacher in a small Connecticut town, and has even married the headmaster's daughter (Loretta Young) as part of his cover. But when one of Kindler's old German associates (Konstantin Shayne) arrives unexpectedly in town, bringing in his wake a sly federal investigator (Edward G. Robinson), Kindler resorts to desperate measures to preserve his secret.