Alfred Hitchcock’s original 1935 version of The 39 Steps is one of those films that’s so seminal that when watched today it can seem like little more than a parade of hoary old clichés; that is, until you consider that The 39 Steps is where many of those clichés originated. The film lays a foundation that countless espionage thrillers have built upon and continue to build upon to the present day. It’s all here: The innocent everyman abroad who’s drawn into a web of intrigue by an encounter with a mysterious and exotic woman; the shadowy international criminal organization whose reach is so extensive that it’s impossible to know who can be trusted; the ardently sought-after “MacGuffin” that sets the plot in motion despite ultimately being inconsequential to the outcome; the criminal mastermind with an identifying disfigurement who hides behind a genteel facade of upper-class respectability; the urbane, witty hero who has a way with the ladies, etc. And while it’s hero takes the train rather than hopping the globe on a luxury airliner, The 39 Steps is worth considering as a necessary precursor to the jet setting spy capers that would follow in its wake some thirty years later.

Based very loosely on John Buchan’s 1915 novel of the same name, The 39 Steps concerns Richard Hannay (Robert Donat), a vacationing Canadian businessman who meets up with an enigmatic woman named Annabella Smith (Lucie Mannheim) while fleeing a ruckus at a London music hall. After convincing Hannay to let her take shelter in his lodgings, Smith divulges that she is an agent working for the British government, and that she is working to prevent agents of a foreign power–men, she says, “who will stop at nothing”–from smuggling air defense secrets out of the country (an enterprise that required a considerable amount of leg work in those days before fax machines and email). Not too surprisingly, someone breaks into Hannay’s digs and pins a dagger in Ms. Smith’s back before the night is through, and she is only able to hand Hannay a map to a location in Scotland and gasp something about “the 39 Steps” before expiring.

Just as you or I would do, Hannay foregoes contacting the authorities, evades Annabella’s killers, and, with map in hand, hops on the next train to Scotland, ready to embroil himself in a deadly game of international espionage despite not being equipped in the least to do so. By this time, Annabella’s body has been discovered in Hannay’s apartment, ensuring that his search for the 39 Steps will be hampered by the unwelcome attentions of both the forces of the law and those of the foreign spies. This situation forces him to ditch the train on which he’s been riding and make his way across the fog enshrouded Scottish countryside on his own, with nothing but his wits and charm to get him by.

Over the course of a series of tight scrapes and daring escapes, Hannay finds himself on the run while handcuffed to Pamela (Madeleine Carroll), a young woman who has reluctantly become enmeshed in his predicament simply as a result of being in the wrong place at the wrong time. This circumstance adds an element of romantic comedy to The 39 Steps, and also allows Hitchcock an opportunity to cheekily flaunt the then stringent restrictions of the British censors–due to the fact that the unmarried couple, because of the handcuffs, must not only share a room, but a bed as well. Ultimately, the initially combative Pamela comes to believe Hannay’s version of events and, after divesting themselves of the cuffs, the two strive to solve the riddle of the 39 steps and foil the plans of Professor Jordan (Godfrey Tearle), the stump-fingered mastermind who masquerades as a pillar of society while scheming to betray his country. Of course, their success depends on them surviving their shadowy enemies’ repeated attempts to eliminate them.

The 39 Steps manages to remain a thoroughly engaging entertainment despite the over-familiarity of so many of its elements, largely due to Hitchcock’s typically masterful pacing and ambitious visual style. The director here pulls off some visuals that, though they would today only be a matter of a few keystrokes, boggle the mind at the thought of how difficult they must have been to achieve at the time (witness, for instance, what’s made to look like a seamless pan from the set-bound interior of a car to the exterior of an actual car speeding off down the road). Robert Donat as Hannay also serves to keep things interesting, and gives the proceedings a distinctly modern flavor, thanks to a sardonic wit that distinguishes him from the more square-cut and upright type of hero we might expect to find in a thriller of this vintage. Madeleine Carroll, likewise, matches him point for point, and the verbal jousting matches between the two serve to keep things crisp and lively.

The 39 Steps was one of Hitchcock’s first international successes, and these seventy-plus years later it’s still not hard to see why. That it’s venerable old formula can still bear results is testament to the fact that such tales of romance and international intrigue, when told with the right amount of wit and style, are a long way from wearing out their welcome.