In mid-June 1932, Eliot Ness, having compiled a list of Frank Nitti's breweries & distilleries, began a series of raids designed to break the back of the Capone empire. This puts the pressure on Frank Nitti, Capone's lieutenant. Nitti calls a meet with Seth Otis and Phil Grier, who jointly own the biggest speakeasy in Chicago, the Hotsy Totsy Club. Nitti tells them he's going to build new breweries and distilleries outside of town, where Ness can't find them, and have the liquor delivered by trucks. It'll take about a month, maybe 6 weeks. The speak owners are shocked, they can't go that long without beer and booze. Nitti tells them nobody better buy booze from out of state and have it hustled in--and he's going to make sure the 2 speak owners "set a good example" for everybody else to obey his orders.
In the meantime, at the State Pen, 2 cons cook up a scheme: the brains is Jason Fiddler, an engineer who will be sprung in a month, and his partner is Matt Bass, who is being paroled tomorrow. Fiddler has devised a plan to pump booze through underground pipes; it'll be Bass' job to sell the idea to Nitti. When Ness raids 4 of Nitti's stills in a row, and they're all empty, he knows Nitti is relocating, but where? Then Ness is called over to the Hotsy Totsy Club; one of the owners, Phil Grier, was found murdered, with an Indiana license plate hung around his neck...obviously he'd tried to smuggle in booze from Indiana, and this was Nitti's warning to other speak owners.
By June 29, Nitti's bookkeeper, Solly Wilks, had purchased 11 farms in the outskirts of Chicago, where new stills would be built, and bought 40 trucks to deliver the beer. Matt Bass, Nitti's former boss in the old days (Bass has spent the last 12 years in prison), meets with him. Matt Bass wants to tell him about the big plan he has, a foolproof way of getting the booze delivered, but Nitti isn't interested; to get Matt back into the organization, though, Nitti offers him a job running a dime-a-dance joint. So Matt Bass gets Seth Otis to put up 210 grand (a big financial gamble on his part), to have miles of underground pipelines laid. For 3 weeks, Ness' roadblocks turn up empty, and Nitti's business is up 40%. But then Ness finds out the booze is being shipped in milk trucks, and shuts him down. Nitti switches to another plan, he has the booze delivered by rail, in oil cars for the fictitious Holloway Fuel Oil Co.
When Ness (who was secretly tipped off by Matt Bass) shuts that down, Nitti's plenty sore. And when Nitti hears that Seth Otis is financing a scheme to smuggle in booze, Nitti figures he's being double-crossed; he tell his hitman Pete Konitz to rub out Otis. Konitz, who seems to enjoy his job a bit too much, replies, "With pleasure." On August 15, the body of Otis is found-- he'd taken a dip in Lake Michigan, with heavy chains around his legs. Nitti meets with Matt Bass, who explains his scheme: the booze is pumped in at a gas station, it goes through underground pipes, and comes out at a terminal, the front being a laundry shop. Nitti asks, what about the workers, won't they talk? Bass says he only needed 4 workers to do the entire job, and they will be paid off...in full (meaning: dead men tell no tales).
Nitti is surprised Bass did all this on spec. And since Bass forced Nitti's hand, by tipping off Ness about the rail deliveries, Bass' life is on the line; when Nitti found out it was Bass who tipped off Ness, Nitti usually has squealers rubbed out. Nitti tells him the plan better work, or else! But when Eliot Ness and Lee Hobson go through the late Seth's papers, they find a mound of invoices for pipes, etc., with Jason Fiddler's name on them; they go to Fiddler's apartment, nobody at home, and find a map with the whole plan outlined. But then Alma, a dancer at the dime-a-dance club shows up, she wanted to see Fiddler; from her, Ness finds out that Fiddler is working for Matt Bass. Now Ness can figure out the whole scheme.
When Matt Bass and Jason inspect the terminal point where the pipes are to pump in the booze, they turn the valve, and it's beer on tap. Then Nitti and his boys, Pete Konitz and Solly Wilkes, arrive. Bass tells Nitti to turn the valve...he does, and nothing comes out; Nitti tries two more. An angry Nitti, with murder in his eyes, says, "What is this, some kind of gag?" Nitti tells him to fix it, quick; "I'll give you 15 minute...and if there ain't booze comin' outta them 3 holes, Pete's gonna put three holes in each of you." Matt Bass and Jason follow the pipeline back, and find out the problem--someone has taken two pipes apart, and the booze is gushing out onto the floor. Bass thinks maybe one of the workers is still alive; but, no, their 4 bodies are still there. It was Ness and his men. They have a shootout with Ness and get gunned down. Frank Nitti gets the hell out of Dodge when Konitz comes running out and informs him that the basement in the gas station sounded like a shooting gallery. The crime scheme orchestrated by Bass & Fiddler had played a sour note.