Racketeer Gus Ducek is fingered to be knocked off. But when the car with the hitmen drives towards him, Ducek's boys fire back with machine guns, turning the tables. One hitman dies, Boley Davis escapes. Watching the botched rubout attempt are Lt. Philip Hedden and Sgt. Davey McCain. Eliot Ness and his men are out to pin the murder attempt on Hedden, since the hitmen were driving one of his cars. November 11, 1931; a group of about 2 dozen Army buddies, who were all in B-Company, 431st Infantry, in WWI, are celebrating the 13th anniversary of Armistice Day. It is their annual reunion, and their host as usual is Lt. Philip Hedden; and beside him, as always, is his sidekick Sgt. Davey McCain. Lt. Philip Hedden regales the men, again, with the story of how he won his medal, the Croix De Guerre; and then he proposes a toast to Sgt. Davey..."To the best top kick who ever did a shavetail's job for him."
Hedden and Davey are a team-- but whereas these former soldiers served their country well back in 1918, they are a disgrace to Chicago now: they are in the rackets, and demand protection money from all the butchers in the city. Lt. Hedden's extortion racket is called the Alliance. However, Hedden doesn't know that Davey secretly hates him; in the War, Hedden got a medal, Davey got a big scar on his face. Hedden is the boss, Davey is a lackey; Davey wants to take over. Ducek used to work for Hedden, now Ducek is his rival; Ducek wants to cut himself in for 30% of Hedden's action. Ness and his men go to all the butchers paying protection money, but they're all too scared to talk. Sgt. Davey goes to Ducek; Davey figures since Ducek double-crossed his former boss, he'll believe him that he wants to double-cross Hedden, too. But Davey is double-crossing both of them. Ducek lets his guard down around Davey; in Gino Romaldi's barber shop, Davey has hitman Boley Davis rub Ducek out, with a machine gun.
Since Gino's shop was wrecked, the barber goes to Ness' office and looks at one book of mug shots after another. Gino is so tired he can't see straight anymore. When Enrico Rossi encourages him, in Italian, to look at one more book of mug shots, Gino snaps, "What's-a-matter, don't you speak English?" But then Gino identifies the hit-man. Gino says he's gotta pay him 200 bucks for wrecking his barbershop. Gino goes to Hedden, and tells him that "Ducek's friend Davey" owes him the money. On hearing that Davey was meeting with Ducek, Hedden figures out that Davey was tipping him off, telling him when Hedden planned to have him hit. Hedden sets a trap for Davey but Davey winds up killing Hedden.
Davey takes over the Alliance and moves in on Hedden's former moll, Megan. Davey figures Hedden's car, money, and booze all rightfully belong to him. There's just one other thing that Davey wants from Hedden. When Davey finds out that Hedden's personal effects have been shipped off to his next of kin, Davey breaks into the express warehouse to steal his medal. Ness and Rossi and Lee Hobson show up and in the shootout, they kill Davey. Lee Hobson philosophizes, "He had it all." In Davey's hand is the Croix De Guerre. Ironically, even though Davey had killed and run the protection racket, all that could have been proven against him was breaking and entering...and stealing the medal, which is only petty larceny. With both Hedden and Davey dead, the Alliance quickly fell apart. Sgt. Davey had a fine record as a Doughboy. He disgraced himself and all that the uniform he once wore stood for by becoming an extortionist like The Butcher's Boy.