On a train departing the nation’s capital, tennis champion Guy Haines (Granger) meets a wealthy young admirer, Bruno Anthony (Walker), who seems to know a lot about his unhappy marriage to clingy Miriam (Elliott). As they converse, Bruno reveals that he despises his overbearing father (Hale), and proposes — theoretically — an “exchange murder.” Guy laughs off the suggestion. But when they reach their end destination, Miriam turns up dead, strangled by an unknown assailant...

Adapted from Patricia Highsmith’s novel, Hitchcock’s “Strangers” is a wickedly smart, noirish spin on the old theme of humanity’s dual (and dueling) nature: good and evil. Having dispatched Guy’s wife, Walker keeps turning up in inopportune places, charismatically taunting the guilt-stricken Granger with the expectation that he return the favor. Hitchcock’s use of “double” images — crossed tennis rackets, train tracks, shoes — to illustrate the dark connection between the two men is dead-on brilliant, but it’s the violent finale on a fairground carousel that makes this suspense film a true classic.