Jazz cornetist Pete Kelly, Jack Webb, and his Big Seven keep the music flowing every night as the house band at the 17 Club, a speakeasy in 1927 Kansas City where Prohibition stirs trouble as much as it stirs up the crowds. The band’s modest earnings draw the attention of Fran McCarg, a ruthless crime boss who wants a cut of their take. When Kelly and his musicians refuse to bend to this pressure, the conflict sets off a chain of bold moves and brutal pushbacks that threaten not only the band's livelihood but their lives.
After the last set, Rudy, the club manager, sends Kelly and his crew to the mansion of Ivy Conrad, a wealthy flapper whose parties are famous for their excess and energy. Ivy, played by Janet Leigh, welcomes them into a world of glamour and excess, and Kelly leaves a message for McCarg to call him at Ivy’s place. The call, however, is intercepted by Kelly’s volatile drummer Joey Firestone, a hot-tempered presence who bluntly refuses McCarg’s demands. On their way back to town, the band is attacked by unknown gunmen, and Firestone is thrown from the car in a brutal moment that foreshadows the violence to come. Al Gannaway, the steady presence among Kelly’s musicians, watches the tension mount as the crew processes what just happened, and the fragile balance holding the group together begins to crack.
The next night brings more danger. Firestone’s rough behavior spills over onto Guy Bettenhauser, McCarg’s top hired gun, and Kelly realises how far McCarg will go to protect his interests. A deadly confrontation erupts inside the club as two gunmen burst through the doors. In a bid to save Firestone, Kelly hurries him to the back, but Firestone is shot in the alley. The night’s tragedy deepens when Kelly returns to his apartment to find Ivy in his bed—an awkward, charged moment that eventually blossoms into a complicated romance and, for a time, an engagement. The frayed nerves in Kelly’s world are echoed by the departure of Al Gannaway from the group, a friend who decides to step away after the mounting strain.
Back at the organizing table, the band leaders convene in secret to decide how to respond to McCarg’s pressure. Kelly, determined to protect his music, is pressed by the others to fight back, but he refuses to bow completely, a choice that tests his loyalty to his art and his crew. McCarg pulls Ivy into his orbit too, pressuring her to influence the band, while Peggy Lee’s Rose Hopkins—a once-talented songbird now struggling with the bottle—tries to keep her voice intact even as the pressures mount. A brutal incident in her dressing room, driven by McCarg’s brutality, leaves her battered and shaken, and Kelly, guided by detective George Tennel and the weight of the case on his shoulders, learns that the mob’s grip is tighter than anyone wants to admit.
As Kelly’s world spirals, Bettenhauser makes a crucial move to obtain incriminating bank checks and documents held in McCarg’s Everglade Ballroom office. If Kelly can come up with $1,200 by daybreak, Bettenhauser promises to help bring McCarg down. Kelly agrees, but the night’s events collide in a crescendo of danger. Back at the 17 Club, Ivy reenters Kelly’s life with a sense of longing, and the couple’s bond is tested once more as the riotously orchestrated music bleeds into a tense showdown.
The climactic sequence unfolds in a blaze of gunfire and improvisation. Bettenhauser climbs into the rafters to gain a better angle, only to be struck down by a clean shot. The gunman who remains targets Kelly, but Kelly wards him off with a improvised defense—throwing a chair that inadvertently causes the shooter to mortally wound McCarg instead. The fateful turn of events leaves the field clear for a grim, hard-won sense of closure: the threat from McCarg is neutralized, but not without cost. The night ends with a sobering return to routine at the 17 Club, where the band resumes playing, Ivy and Pete briefly find common ground, and Rudy looks for new, questionable ways to turn a profit to keep the club afloat.
In the aftermath, the story circles back to the core themes of loyalty, art, and the shadowy intersection of crime and music. The music remains the heartbeat of the club, even as the city’s underworld circles closer, and Kelly faces the delicate balance between pursuing justice and preserving the art that defines him and his crew. The film closes on a world that has not forgotten the violence it endured, but one where the music and its players press on, stubborn and resilient, at the 17 Club.
