The film is a collage effect of old black and white movie clips from films of the 1940s and 1950s, with more recent footage of Martin and other actors (including Carl Reiner, Rachel Ward, and Reni Santoni) similarly shot in black and white. When everything is put together, the original dialogue and acting becomes part of a completely different (and ridiculous) story. This was the last film for both costume designer Edith Head and composer Miklós Rózsa.
Among the actors who appeared from classic films were Edward Arnold, Ingrid Bergman, Humphrey Bogart, Wally Brown, James Cagney, William Conrad, Jeff Corey, Joan Crawford, Bette Davis, Brian Donlevy, Kirk Douglas, Ava Gardner, Cary Grant, Alan Ladd, Veronica Lake, Burt Lancaster, Charles Laughton, Charles McGraw, Fred MacMurray, John Miljan, Ray Milland, Edmund O'Brien, Vincent Price, Barbara Stanwyck, Lana Turner and Norma Varden.
Film editor Bud Molin faced the challenge of linking Film Noir classics and contemporary footage, which ran at different speeds.
In the opening scene, John Hay Forrest, noted scientist, dies in a single-vehicle car accident. His daughter Juliet (Rachel Ward) faints upon seeing the headline when visiting Rigby Reardon's (Steve Martin) office to investigate the death. While fainting, her breasts are "shifted out of whack", prompting Reardon to adjust them, to Forrest's gratitude (important later). She gives him a key to Dr. Forrest's lab, where he finds two lists: "Friends of Carlotta" and "Enemies of Carlotta". He also finds an affectionately autographed photo of Kitty Collins, whose name appears on the "enemies" list. His search is interrupted by an "exterminator" (Alan Ladd, in "This Gun For Hire"). They share cookies before the exterminator starts shooting. Reardon plays 'possum while Ladd frisks him for the lists.
Reardon manages his way to Juliet's place, where she sucks out the bullet, snakebite-style. She points Reardon to the club at which Kitty sings. Juliet also discloses a note to her father from her brother-in-law, Sam Hastings, which in turns discloses that a dollar bill Dr. Forrest gave him "for safekeeping" is in Sam's sugar bowl. They are no longer related, as her sister Leona divorced Sam because of his alcoholism (the sugar bowl and alcoholism references set up use of a clip from Lost Weekend). Reardon calls Leona Hastings (Barbara Stanwyck, in Sorry, Wrong Number), but finds her seemingly speaking gibberish—the plots of the two movies being unrelated. Juliet explains this away as a psychiatric condition. On the way out, Juliet asks Reardon to leave further news with the butler or cleaning woman (conspicuously not "maid"). Mention of the latter sends Reardon into a homicidal rage (an homage to the old Slowly I Turned vaudeville routine), due to his own father's infidelity—important later to incorporate another movie clip and at the film's conclusion.
Reardon tracks down alcoholic brother-in-law Sam (Ray Milland, from his performance as alcoholic Don Birnam in Lost Weekend) and gets Dr. Forrest's dollar, which has Friends of Carlotta (FOC) names scrawled on it—including Kitty Collins and Swede Anderson (Kitty's boyfriend). Reardon tracks down former father flame Kitty Collins (Ava Gardner, this clip from The Killers) at the Brintwood Room. He asks if she's one of Carlotta's friends, which causes her to leave abruptly. He trails her to a restaurant, where she ditches her brooch into her soup. The retrieved brooch contains a list—Enemies of Carlotta (EOC). The names are all crossed out, except Swede Anderson's (despite Swede's seeing Kitty at the time!). Reardon visits Swede (Burt Lancaster, also from The Killers) before he's "crossed out" too, but is unsuccessful. Swede dies before he gets any lines in the scene.
Back at the office, Juliet sucks out the bullet Reardon took in the hit. Reardon calls Philip Marlowe (Humphrey Bogart, from The Big Sleep), his mentor, for assistance. Juliet hands over a key from Dr. Forrest's desk, a key to a train station locker. The accompanying note, "most recent rat", tells Reardon it's to locker 1936, the last year of the rat. Upon exiting, she asks Reardon to call with any progress. "You know how to dial, don't you? You just put your finger in the hole and make tiny little circles," a tiny little nod to To Have and Have Not. Marlowe arrives, and picks up the EOC list to check against unsolved murders.
Reardon goes to Union Station to collect the contents of locker 1936—more Carlotta "frenemies" lists. Reardon is followed by a "handsome guy" (Cary Grant, from Suspicion) onto the train ride to visit F. X. Huberman, a name on the Carlotta lists. Grant falls asleep, ending up incidental to the plot. F.X. Huberman (Ingrid Bergman, from Notorious) is throwing a party, and flirts with Reardon (represented by Cary Grant's silhouette), now calling him handsome. While he's in the bathroom, she steals the locker key (represented by Claude Reins' wine cellar key).
Reardon wakes up back up at his office, where Juliet informs him brother-in-law Sam Hastings fell out of a window to his death. She also has a New York Times reference for him from her father's office. The reference is to an article about the Immer Essen, a South American cruise ship owned by Walter Neff. Sam Hastings was on its last voyage—an improbable coincidence that piques Reardon's curiosity. When Marlowe (Bogart, in a clip from The Big Sleep) calls, Reardon quizzes him about Neff. Neff cruises supermarkets looking for blonds, a contrivance to include Fred MacMurray's Walter Neff from Double Indemnity.
Juliet offers to dye her hair to serve as bait, but Reardon is protective of her as more than a client. He first tries to recruit Monica Stillpond (Veronica Lake, from The Glass Key), but she's not the pushover she used to be. Next he tries Doris Devermont (Bette Davis, from Deception), but he ruins his chances with her by strangling her for saying "cleaning woman". Then he successfully recruits Jimmie Sue Altfeld (Lana Turner). Reardon meets with her father (Edward Arnold) to soften him up to the danger he's putting Doris in, with little success: "Can I use her underwear to make soup?" The two Altfeld clips are linked by the lines "He never had a dog," and "Pick that up". Kirk Douglas, in a neighboring office, has three of his thugs beat up Reardon. This convinces Reardon to give up on recruiting a blond as bait and meet Neff himself.
Back at Neff's, Reardon slips him a Mickey and finds an article identifying the Immer Essen's captain, a Capt. Jarrett, who refuses to talk to anyone about it but his mother—a pretense for including clips of James Cagney from White Heat. Reardon then dresses as Jarrett's mother to visit Jarrett in prison without arousing the prison guards' suspicion. He tries to win Jarrett's confidence by explaining the Friends of Carlotta are after him. Reardon doesn't learn anything from Jarrett though, so he cashes in a favor with the warden to act as a prisoner for a few days. Somehow Jarrett turns out to be a Friend of Carlotta after all, kidnaps Reardon on a jail break, and shoots him while he's still in the trunk of the getaway car (calling Reardon "Parker"). This becomes the third bullet Juliet sucks out. She carelessly sticks her finger in his bullet hole though, so she goes to the drugstore for something to help the pain. On her way out, a call comes in from an old flame (Joan Crawford, in Humoresque). Juliet overhears parts of it, misunderstands, and closes the case. Marlowe calls and tips Reardon off that Carlotta is an island off Peru: "It's not a woman's name. It's a place." (perhaps a nod to The Man Who Knew Too Much). Marlowe suggests a certain cafe there, and Reardon finds Kitty (Ava Gardner, this time from The Bribe), Dr. Forrest's old flame, there. Carlos Rodriguez, a local policeman from Reardon's gun-running past, warns Reardon of the locals, including Kitty's new boyfriend, Rice. The next day, one of the characters Carlos warned Reardon of (Charles Laughton, also from The Bribe) approaches him with—a bribe. This and the next archive clip are the only ones in which Reardon is correctly referred to by name. Charles Laughton tries to pay Reardon to leave the island.
The bribe having failed, Kitty drops by Reardon's room to slip him his second Mickey of the film. This scene has the first archive clip mentioning Carlotta. Before he passes out, Carlos calls to tell him Rice is in town with a group of Germans. Reardon wakes up to see Rice (Vincent Price, also from The Bribe) over him. Reardon escapes somehow. Pursuing Rice, they pass a fireworks celebration, much of it archived, including a display reading "Fiesta de Carlotta". Shooting Rice, Reardon frisks the corpse for instructions leading him to a Nazi hideout where Juliet and her (alive) father are captive.
It turns out that Dr. Forrest had been tricked into divulging a secret cheese mold by Nazis posing as a humanitarian organization. Once he discovered their true intent, to use the mold's corrosive properties to destroy America and make a comeback (the movie is set after WWII), he assembled a list of Nazi agents (a.k.a. Friends of Carlotta) to disclose to the FBI. He was abducted before he could reach the FBI. The agents faked his death to prevent a police investigation. A passing cruise ship, the Immer Essen, witnessed the corrosive effects of the Nazi's mold tests on a small island. To prevent further discovery, future cruises were canceled (Walter Neff, naming his ship in German, would be sympathetic...) and all passengers were targeted for murder (Enemies of Carlotta). To escape captivity, Juliet gets the lead Nazi to say "cleaning woman." This triggers another fit in Reardon, who overcomes them all. Reardon ultimately saves the day, but not without his "willy" being "shifted out of whack". Fortunately, Juliet noticed—and adjusts it for him.
This was legendary Costume Designer Edith Head's final film. There is a tribute to her in the closing credits denoting this. Fittingly, the film features many of her earlier designs in cleverly edited clips from old movies.
Also the last film of legendary composer Miklós Rózsa. This was ironic since he was also asked to rescore music for original images that he had worked on in the 1940s and 50's.
The car accident at the beginning of the movie (the fake killing of the scientist) is taken from Keeper of the Flame (1942). The movie however is not credited as an item being quoted from.
The movie was initially planned by Martin and Reiner to be a '30s-era movie titled Depression. After Reiner incorporated some footage of a '30s star into the movie, he and Martin decided that the entire movie should be done that way, and re-wrote it into a mock-detective story.
Rigby Reardon tells Lana Turner he left her sitting at a counter at Schwab's. Lana Turner is rumored to have been discovered sitting in a Schwab's drugstore.
At the end of the film, as Rigby Reardon and Juliette Forest are passionately kissing, Steve Martin, in voiceover, announces that there will be a sequel (which features a possible nude scene by Juliette) and that it would be in cinemas soon. No sequel has been produced.
Initially, Steve Martin's character was written to tell off Humphrey Bogart's "mentor" character as an old has-been. The scene in which Martin did this was restored for network-TV showings.
It is alleged that the scene where the Nazi officer is killed and falls on the map showing the locations to be destroyed by their secret weapon, in which he claims "At least we got Terre Haute", was a retort to a public humiliation of Martin by that city, located in central western Indiana, over a claim by Martin published in a newspaper not long after he had performed his stand-up comedy routine at the local civic center that Terre Haute was "Nowhere USA".
The film has entered the political lexicon through the terms "enemies of Carlotta" and "friends of Carlotta", a reference to two lists of people in the movie. "Carlotta" is an island where the bad guys are. "Enemies of Carlotta" are therefore the good guys.
"Laugh ... or I'll blow your lips off" "I'm sorry - I guess I just don't like being called a meal ticket."