Ladd is Raven, a San Francisco hitman with a soft spot for cats, who kills a blackmailer named Baker. Raven retrieves a stolen chemical formula from Baker and brings it to his employer, Willard Gates (Laird Creegar). Gates then double-crosses Raven by reporting the money he gave Raven for the job as stolen from the bankroll of his company, Nitro Chemical. Raven goes on the run from the police, led by visiting LAPD detective Michael Crane (Preston).
Meanwhile, Crane's girlfriend, stage singer and magician Ellen Graham (Lake), is enlisted by the feds to get info about Nitro Chemical by auditioning for Gates, who also owns some nightclubs. The government believes that Nitro Chemical is selling chemical weapons to the Japanese. Ellen takes the train to Los Angeles to start her job at Gates's club and spy on Nitro—and winds up in a seat next to Raven, the fugitive.
This Gun for Hire made a star out of Alan Ladd, who had been working as a bit player and in small parts for years (he's one of the reporters in Citizen Kane). He and Lake were a successful screen couple due in part to their chemistry and also because they were both short—five foot zero Lake matched up better with 5'6" Ladd than other actresses did. Lake and Ladd would go on to make four films noir together.
This work exhibits the following tropes:
- Anti-Hero: The protagonist is a hitman who has no qualms about killing innocent bystanders merely for being witnesses. He also kills a police officer to get out of a bind.
- Assassins Are Always Betrayed: After Raven kills someone his employer reports a fake robbery and gives the police the numbers of the bills with which he paid for the murder.
- Blackmail: Baker tries this with Nitro Chemical. It was a bad idea.
- The Chanteuse: With a twist, as Ellen's nightclub act combines singing with magic tricks.
- Contract on the Hitman: Employers of hitman Raven pay him with recorded bills and report him as a violent robber, telling the police to shoot to kill. Overall it's a stupid plan.
- Dressing as the Enemy: Helpfully, Nitro Chemical is conducting a gas attack drill when Raven gets there. Raven attacks Gates' man Tommy, and takes his uniform and gas mask. This allows him to get to Gates.
- Empathic Environment: There is a well-timed clap of thunder after Gates catches Ellen in a lie and confronts her about Raven.
- Establishing Character Moment: Raven receives a note giving a man's location. He pulls out a gun and puts in in his bag, establishing him as a tough guy. Then he opens the window of his room and gives a saucer of milk to a stray cat.
- Evil Cripple: Alvin Brewster, the president of Nitro Chemical, who is very old, wheelchair-bound, and unable to speak above a whisper. He is also the Big Bad who's been sending weapons and intelligence to the Japanese, and he tries to kill Raven.
- Film Noir: Murder, betrayal, a sexy chanteuse—sure.
- The Film of the Book: Adapted from a 1936 novel by Graham Greene.
- Freudian Excuse: Raven was made an orphan at an early age and was made to live with his aunt who was extremely abusive, to the point of one day hitting him with a hot clothes iron, giving him his iconic wrist injury in the process. Raven killed her with a knife in retaliation and as a result was placed in a reform school for the rest of his youth, where he suffered even more abuse. It is used as the explanation for why Raven has no problems with killing for a living and so deeply resents society.
- He's Dead, Jim: Brewster's aide checks him for about five seconds and doesn't even look for a pulse before declaring him dead.
- Hidden Depths: Raven the hard-bitten hitman has a fondness for cats. Later, he tells Ellen how he got his misshapen wrist—when he was a teenager his abusive aunt smashed it with a red-hot iron.
- Loners Are Freaks: Raven is shown to live alone and he evidently very much prefers it that way. His landlord and the cleaning lady is shown to dislike him for his distant behavior, to the point where they relish in the fact that he is about to be arrested. In a later scene, Raven tacitly admits to Ellen that his soft spot for cats comes from the fact that he sees cats as creatures who are perfectly adapted to not having to depend on anyone, ultimately what he aspires to be.
- Professional Killer: Duh, "this gun for hire." Raven is in fact a pretty bad guy—he kills an innocent woman in the opening scene to cover his tracks, he kills a policeman to escape, and he was about to kill Ellen when he was interrupted.
- The Quiet One: Raven seems to outright dislike saying any more than he feels he needs to and adamantly avoids small talk. In fact, most of his lines is him ordering people around. The only one he truly opens to up during the story is Ellen.
- Redemption Equals Death: Instead of just killing Gates and Brewster, Raven does as Ellen asked him and gets them to sign confessions. This comes at the cost of his own life.
- Scaramanga Special: Brewster has a pen which also functions as a gun. He tries to shoot Raven but misses.
- Sexy Whatever Outfit: In one of the musical numbers, Ellen at first appears to be Dressed Like a Dominatrix holding an oversized riding crop. Then it's revealed that the implement is a fishing pole: she's a sexy angler, complete with shiny, shiny hip waders.
- Sissy Villain: Gates is effeminate and persnickety, and quails at Tommy's description of how he's going to kill Ellen.
- Sleep Cute: Gates draws the wrong conclusion about Raven and Ellen after seeing them sleeping next to each other on the train.
- Stage Magician: Ellen's act is a combination of singing and magic.
- Stockholm Syndrome: Ellen is awfully willing to help a murderer who has been dragging her around Los Angeles at gunpoint. Of course, he did rescue her from Gates's mansion.
- Trail of Bread Crumbs: Ellen the stage magician drops cards from her deck to help the cops find her, after Raven drags her away.
- Train-Station Goodbye: The usual, with Michael following along after Ellen's train as it pulls away.