LAPD Sergeant Walter Brown (Charles McGraw) escorts Mob widow Mrs. Neall (Marie Windsor) on a train ride to testify. But a hitman kills Brown's partner (Don Beddoe) and Brown discovers several sinister characters onboard the train. Trying to hide Mrs. Neall, he spars with a nosy crook (David Clarke) and resists a bribe from a crime boss (Peter Brocco). He also draws out the attention of Ann Sinclair (Jacqueline White), a single mother who isn't what she seems.
Crisply paced and cleverly structured, The Narrow Margin never loses interest. Fleischer and cinematographer George E. Diskant craft a marvelous atmosphere. Beyond the noir-required smoke and shadows, Fleischer inundates us with striking touches: a victim's smashed cigar stub, a jump cut from Mrs. Neall's nail file to train wheels, Brown outwitting an antagonist by spying his reflection on a window. The movie lacks a musical score, aside from Ms. Neall's phonograph underscoring several scenes, allowing train whistles and sliding doors to enclose viewers alongside Brown.
Fleischer and writer Earl Felton make the most of their 72 minutes, barely pausing for exposition or plot. There's enough misdirection and sharply sketched characters for a dozen thrillers: Mrs. Neall's acid resentment; a fat bystander (Paul Maxey) who seems overly interested in Brown's doings; Mrs. Sinclair and her nosy son (Gordon Gebert), who insinuate themselves into the plot. It's all on Brown, who's gritty professionalism's tested by duplicitous colleagues. Midway through he finds the gangsters targeting Mrs. Sinclair, discovering he's been a dummy all along.
Charles McGraw is perfectly cast, a rock-jawed cop whose professionalism is unshaken by his uncooperative charge or glad-handing crooks. Marie Windsor makes her character unremittingly nasty and selfish, unmitigated by her last-minute revelation. Jacqueline White makes an appealingly sweet distraction, while David Clarke, Peter Brocco and Peter Virgo make a menacing villain trio.
Thrillers don't come much better than The Narrow Margin. Packing admirable style, craft and tension into its 72 minute run time, it's among the best of its genre.