from "Crime Pays: The Hollywood Gangster, 1930-1938" http://xroads.virginia.edu/~UG02/gangsters/littlecaesar.html
Little Caesar - Plot Synopsis
The plot revolves around the quick rise and quicker fall of Rico Bandello (Edward G. Robinson) and his association with his friend Joe Massara (Douglas Fairbanks Jr.) who wants out of the gangster business. The first scene opens with a long shot of a gas station. The audience sees a car drive up, and watches as the attendant is shoved back into the store and three gun shots are heard. The next scene cuts to Rico (Edward Robinson) and Joey (Douglas Fairbanks Jr.) in a dinner. They turn the clock back for an alibi, and discuss the success of a gangster known as "Diamond" Pete Montana who recently had a banquet given in his honor. Rico wants to be just like Pete. Joey talks about getting a girl and money in the city and then settling down and going back to his dancing career after his life as a gangster. He also reveals that he never would have gotten into crime without Rico. Rico dismisses Joey's dream saying that the important thing was not women or even money, but being somebody. He decides that they are going to the big city, "where things break big"
When they arrive at the unidentified city Rico wastes no time and joins a gang run by Sam Vettori (where he gets his mob name Little Caesar) while Joey gets a dancing job at the Bronze Peacock. His partner, Olga Strassoff (Glenda Farrell), falls in love with him quickly (in 1 minute of actual film time) and they embrace passionately. She discovers his gun and asks him to give up the gangster life. He replies that he could never get away with it. The audience next witnesses about a meeting at Arnie Lorch's gambling house where Sam Vettori and Rico (who has now become Sam's body guard) meet with "Diamond" Pete Montana. Rico is ordered to wait outside because of his itchy trigger finger. The gangsters discuss the new crime commission and the fact that the next hit needs to be victimless. Montana warns Rico to "take it easy with that cannon of yours" while Rico admires the expensive tie pin and ring that Pete is wearing.
Back at Vettori's club front the gang plans a robbery of the Bronze peacock and the audience sees Rico getting more and more ambitious. Tony the river says that he is scared and is accused by Rico of turning yellow. Joe arrives late and upon learning that the gang is to rob the Bronze Peacock, he pleads with Rico to get him out. A pained Rico replies, "You're gonna be in on this and you'll like it!"
When the robbery occurs, Joe acts out his part and the Peacock is robbed successfully, but as they are turning to leave Rico unnecessarily shoots the crime commissioner. Joe is noticeably shaken and Olga tries once again to turn him from the gang. Tony attempts to get rid of the car, but is too nervous and crashes it. Back at the hideout, Rico splits the money his way and takes over control of the gang from Vettori. The cops come and the gang is questioned about the crashed getaway car. Tony defaults from the gang and Rico shoots him down on the steps of the church before.
Time passes and Rico is given a banquet in his honor, just like "Diamond" Pete had. His picture is taken by the tabloids, and he gives a short awkward speech. The cops show up, but have nothing. The headline the next day is in reference to the banquet and Joe overhears Arnie Lorch talk about killing Rico, "and when they find him, it won't be no banquet that Rico gets. It will be a wake." He telephones Rico about the threat to his life.
Rico seems oblivious to the danger, he is next shown buying ten newspapers with his picture on the cover and then walking down the street with them in broad daylight with no protection a car speeds by the shots are heard. Rico is wounded in the arm and defiantly shouts that they are bad shots. After hearing about Joe's call he vows to pay Arnie back for the wound, and in the next scene accomplishes it, forcing Arnie out of town and taking over his business. The next day he dresses up to meet his new boss (Big Boy), now that he has displaced Arnie. Walking around Big Boy's house, Rico's love of material things is obvious, but he can't appreciate them, admiring a golden frame but not the more valuable painting and flicking cigar ash onto an expensive rug. Big Boy takes him in and offers him Pete Montana's territory. Rico shakes his hand and they seal the deal.
Time passes as illustrated by a title card that states, "Rico continued to take care of himself, his hair and his gun -- with excellent results." The audience then sees Rico in a mansion similar in opulence to Big Boys with a fancy tie clip and a ring like the one that he once admired on Pete Montana. Joe is invited over, and Rico tries to convince him to come back to the gang, offering him a partner position on the north side. Joe refuses and Rico is hurt. He accuses Joe of going soft and blames Olga threatening her life. Joe declares he loves her, and Rico becomes hysterical threatening them both. They are interrupted by a call from Big Boy. Rico assures his boss that Joe will be his partner, while Joe slips out the back and runs to Olga's apartment. She calls the police, and Rico and his right hand man burst in.
The henchman yells to shoot, and Joe implores Rico to get it over with. But he is unable to. The shot goes to a close-up of Robinson's face and pans in on his stricken expression. The henchman yells that Rico has gone soft and pulls out the gun, but Rico deflects the aim and it hits Joe in the arm. The police arrive and Rico and his man flee. Olga tells the police that Joe will testify, and the detective sends the men after the gang. Rico's right-hand man is killed, but he escapes. Rico reflects: "This is what I get for liking a guy too much." Rico hides in the house of an old woman who cuts a hard deal, and out of the ten grand he has hidden there, he only gets 150 dollars.
More time passes and another card reads, "Months passed -- Rico's career had been like a skyrocket -- starting from the gutter and returning there." He has started drinking and is sleeping in a 15 cent a night flophouse. The other transients at the house read aloud a newspaper article in which the detective insults Rico. He is visibly pained and calls up the police who promptly have the call traced. They find him walking down a deserted street and the detective shoots through a billboard, ironically of Joe and Olga's new dance routine, killing Rico.