The film opens in the Los Angeles basement of the United Defenders (UD), a veteran-backed, fascist-leaning group, where the mood blends camaraderie with menace. Joe Donahue, Jimmy Clark, tries to walk away after discovering the scam, but Fred Stalk, Sheldon Leonard, and another goon press him. Stalk kills Donahue to silence the defector. UD leader True Dawson, Emory Parnell, closes a meeting as attendees depart, and UD secretary Ann Dwire, Nancy Coleman, covertly photographs the crowd with her watch, cataloging the faces for later use. Stalk privately slips Dawson the news of Donahue’s death, and Dawson lays out the ruse: he will keep fanning anger among veterans to extract UD dues and Defender novelties, certain that a volatile mood will keep the money rolling in.
Meanwhile, in Chicago, Ann Dwire, Nancy Coleman, is really an undercover investigative reporter for a muckraking magazine, working within the LA Ud scene from the inside. At her apartment she reads a letter from her editor suggesting she has enough material to return home and file her story. Claiming she’s taking a personal trip to Chicago, she says goodbye to her colleagues and prepares to move.
In Chicago, Steve Fuller, Michael O'Shea, tails Ann as she heads back toward LA; he orders his driver to shake him off, but the cab crashes. Steve locates Ann in the hospital, where she is unharmed but suffering from amnesia. He fabrics a cover story—telling her they are engaged—and escorts her back to Los Angeles, where memory remains elusive.
Back in LA, memory clouded but gradually returning, Ann resumes work with the UD and even joins Dawson in one of his fundraising pitches. Sally Donahue, Cay Forester, the missing Joe’s widow, searches for her husband while Steve uncovers letters Sally wrote to Joe hidden in Stalk’s room, hinting at the UD’s murderous reach. The evidence worries Ann, and she shares the troubling details with Dawson, though seeds of doubt begin to grow.
A blow to her memory—when she questions Stalk, Sheldon Leonard—is enough to jolt her recollection, and she ends up bound in the basement with Steve, who reveals that he is an undercover Los Angeles detective. The two pieces of the puzzle begin to align: the UD is part of a broader, anti-union, strong‑arm network. A shadowy overseer, Mr. X, William Gould, discreetly directs Dawson to rough up a group of veterans protesting for affordable housing, with the plan to use the ensuing melee as cover for murdering Ann and Steve.
The protagonists escape the basement and rush to warn the protesting veterans. They corner Dawson and force him to lead them to Stalk, who fears Dawson will pin the crime on him. In a final confrontation, the two men shoot each other, the UD is exposed, and the elusive Mr. X slips away, leaving the network and its dark connections largely unscathed for the moment.
