Not only does Inspector Bill Davis (Richard Cortez) take everything seriously, but he also is a paragon of efficiency. The unflappable Davis always has reassuring words for anybody who has a problem with the postal service. Davis sorts out all the problems that citizens have without blowing his cool. Popular singer Connie Larrimore (Patrick Ellis) meets Davis aboard a flight from Washington, D.C. to Milltown, during stormy weather. The pilots are struggling to land, but a storm blinds them. Ground Control talks the pilots safely down. During the story, our heroine sings to soothe some frightened passengers, with a youngster providing accompaniment on his harmonica. The press plasters Connie's commendable singing exploits across the front page story. . Bela Lugosi makes his first appearance as Gregory Benez at the airport. The natty nightclub owner has Connie under contract to sing in his nightclub The Golden Eagle. Eventually, we learn Benez has shady dealings with the mob. He owes Alfred Carter, ‘known to have financed many nightclubs,’ $50-thousand. Worse, Benez is two weeks tardy on his payment. At the airport, Connie reacquaints herself with an old friend from high school in Milltown. The friend turns out to be Bill’s younger brother Charlie (Michael Loring), and Charlie wants to rekindle the flame. Seven years have elapsed since they went their separate ways. Our hero’s introduction to Connie has a memorable moment. Charlie points out his brother works for the post office. Slyly, Connie reminds Charlie that it has been a long time since they played post office. Brower and McCoy milk this moment again later in the action for dramatic emphasis. Connie learns Charlie works for the Federal Reserve Bank. Charlie is in charge of all the money that the Federal Reserve wants to remove from circulation. He tells Connie about a shipment of used bills, approximately $3-million worth of bills.
About 31 minutes into the action, our handsome hero catches a plane to Yarborough where heavy rains have washed out a bridge and cut off the town. Meantime, Davis relocates the Yarborough Post Office to higher ground. Later, Benez and his accomplices knock over the armored car, kill a postal employee, and steal the millions. Benez is nowhere around when his henchmen hit the Postal truck. Of course, Davis is not happy. Brower doesn’t depict the attack on the driver of the postal vehicle. Everything occurs off-screen. Afterward, we see the postal vehicle tipped onto its side. Benez’s henchmen careen away from the scene with a bundle of money. Later, a man named Ritter (Harry Beresford) apprises Davis about the money bags. They use a boat to reach the robbery vehicle and find $20-thousand. Davis assures Ritter that he will figure in any reward. Meantime, Davis learns that only three people knew about the $3-million, and one of them was Charlie. Initially, Charlie assures his brother Bill that he had nothing to do with the robbery. It looks like Charlie and Connie are to be implicated until Connie agrees to flush out Benez. When Bill investigates the robbery vehicle, he discovers the car belonged to Charlie. Bill puts Charlie on the hot seat about the robbery, and his brother comes back to him two hours later with the explanation. Charlie let Connie borrow his car and somebody stole the car from Connie.
Altogether, "Postal Inspector" qualifies as a routine potboiler about Postal Inspectors. The stock footage of the flood scenes is impressive. One desperate African-American scrambles to seize a chicken. Lugosi plays Benez with considerable restraint. The joke about the elderly woman who solicits proposals of marriage through the mail with a photograph of a young, beautiful woman is hilarious. The villains use a boat to elude the authorities, but Charlie and Connie disrupt their getaway. Newspaper headline state that the mail robbers are scheduled to serve 20 years to life. The mail robbery prompts the Federal Reserve to stop transferring old bills. Instead, they decide to mutilate the bills in the future. Charlie and Connie serenade Bill over the phone and apprise him of their impending marriage.