World War II veteran Tod Shaw (Sterling Hayden) is the sheriff of a small California town with the unlikely name of Suddenly. When word comes down that the President of the United States will make an unscheduled whistle stop at the train station, Secret Service agents descend on the town and work with Tod to make sure things go smoothly. They take particular interest in a house on a hill overlooking the station. As it turns out, a retired Secret Service agent, Peter "Pop" Benson (James Gleason), lives there, along with his widowed daughter-in-law Ellen (Nancy Gates) and her young son Pidge (Kim Charney).
Before Tod and the Secret Service can make it to the house, though, three men claiming to be FBI agents show up: John Baron (Sinatra) and his henchmen Bart Wheeler (Christopher Dark) and Benny Conklin (Paul Frees, in a rare live-action acting role). While they claim to also be in town to guard the President, when Tod and Secret Service chief Dan Carney (Willis Bouchey) ring the doorbell, the ruse is revealed: Baron and his men are hired killers, and they've commandeered the house to assassinate the President by firing a high-powered rifle from a window, holding everyone hostage and threatening their lives.
The film has gained notoriety not only for Sinatra playing a Big Bad, but for being eerily prophetic to the JFK assassination, which has led to a number of myths and misconceptions about the film over the years.
This film contains examples of:
- Anyone Can Die: Several bursts of gunfire in the film, and the unexpected deaths of Carney, Benny, Bart and Jud the TV repairman dial up the tension quite a bit.
- Arc Words: "You don't have the guts!"
- Because I'm Good at It: John brags about his prowess in killing people being the reason why he's a hit man, constantly bringing up the Silver Star he won in the war for killing dozens of Germans.
- Bond Villain Stupidity: John could very easily just kill everyone, but he sure loves his Evil Gloating. Tod is Genre Savvy enough to recognize this; he points out that John is way too chatty, and if they keep goading him into giving Motive Rants, he'll get distracted and start screwing up.
- Chekhov's Gun:
- Literally a gun belonging to Pop, which gets used to thwart John at the climax.
- Also the broken TV set, which gets used as part of an Electrified Bathtub-type trap for the assassins later.
- Cutesy Name Town: As Slim the deputy explains in the opening scene, Suddenly, California got its name in the Gold Rush years when fortunes were won and lost quickly. But it's a Meaningful Name for the purposes of this story, since many major plot developments indeed happen quite suddenly.
- Everytown, America: Suddenly had a wild-and-woolly past, but by 1954 it's mellowed out into one of these.
- Fourth Wall Psych: During a couple of his monologues, John walks up to the front of the frame and looks directly into the camera.
- Freudian Excuse: John blames his alcoholic parents for why he's so evil.
- Halfhearted Henchman: Bart and Benny both show some reluctance to follow John's orders.
- Hidden Villain: John points out that he's only getting paid to kill the President, and has no political motivations to do so. He's not even aware of who exactly hired him to do it.
- The Mafia: John, Bart and Benny are obviously organized crime Mooks, but having Sinatra as the gang leader evokes this specifically.
- Mama Bear: Ellen walks a tightrope throughout the story, trying not to agitate John so Pidge won't be harmed. At the end she fires the shot that wounds John, allowing Tod to finish him off.
- Mr. Fixit: At the beginning, Pop tries to fix the TV set, boasting of his expertise with electronic devices. He very nearly electrocutes himself in the process.
- Shell-Shocked Veteran: John maybe fits the trope, but it's clear that he had major psychological issues even before he joined the service. Tod susses out the information that, despite his Silver Star, John wound up getting discharged on a Section 8.
- The Sociopath: John fits the bill, but as he gives his Motive Rants, it's revealed that he's quite a neurotic mess, who probably got in over his head with the assassination plot, and he becomes a Nervous Wreck when his plans start to unravel.
- The Stool Pigeon: A mortally wounded police informant in Los Angeles tipped the cops off about the assassination plot, allowing the Secret Service to get a head start in setting up protection.
- Villain Protagonist: Frank Sinatra as John Baron gets top billing and dominates the film.
- Would Hurt a Child: John repeatedly threatens to kill Pidge if Ellen, Pop and Tod don't comply with his orders.