A successful professor has his life disrupted by a secret from his past - in his college days he became a member of a powerful secret society, and now the society has a job for him.
The film depicts a successful economics professor, Dr. Andrew Patterson, who discovers that an elite fraternity he joined as an undergraduate is really a callous banking and business cabal that obtains wealth and power for its members through nefarious practices.
Professor Andrew Patterson (Glenn Ford) returns to his alma mater, the College of St. George in San Francisco. He is attending the initiation of a new member into a secret society, the Brotherhood of the Bell. The man who initiated Patterson 22 years earlier, financier Chad Harmon (Dean Jagger), is presiding at the ceremony. Harmon gives Patterson an address and instructs him to go there to receive an assignment from the society; Patterson has been selected to prevent Dr. Konstantin Horvathy (Eduard Franz) from accepting a deanship at a college of linguistics. The Brotherhood wants this post for one of their own. Patterson is given dossiers of people who helped Horvathy defect to the United States, and he is to threaten to reveal these to the government of Horvathy's homeland if Horvathy accepts the new post. Against Brotherhood policy, Patterson consults Harmon about the legality and ethics of his assignment. Harmon tells Patterson to do it and be grateful that more is not asked of him.
Patterson returns home to Los Angeles and immediately contacts Dr. Horvathy. Unable to persuade him to decline the position, he presents him with photostats of the dossiers. Horvathy, who is a lifelong refugee from Fascism and Communism, commits suicide. Remorse causes Patterson to confide in his wife, Vivian (Rosemary Forsyth), and his father-in-law Harry Masters (Maurice Evans), and he announces a desire to reveal the Brotherhood's actions to the public.
The original dossiers remain in Patterson's possession. Masters takes him to see Thaddeus Burns, an agent of the Federal Security Services (the film's fictional version of the FBI). Masters is secretly an agent of the Brotherhood who is trying to recover the documents from Patterson; he later denies taking Patterson to see Burns. Vivian's family believes Harry's version of events, alienating Patterson. Vivian leaves him.
Patterson is informed that the successes he and his father (Will Geer) achieved in life were not their own, but benefits of his membership in the Brotherhood, "gifts" produced by the society's covert manipulation. After Patterson goes public with his exposé, his father, the CEO of a multimillion dollar company, is singled out by the IRS for fraud. The older Patterson lashes out against Harry Masters in response, suffers a stroke and dies. Andrew is relieved of his professorship at the behest of the Brotherhood of the Bell.
Patterson finds himself increasingly isolated, and reaches rock bottom when he appears on a local television talk show. The host (William Conrad) humiliates him on-air, and Patterson lashes out at him. Patterson is arrested, but is bailed out of jail by his former boss, Dr. Jerry Fielder (William Smithers). Fielder believes Patterson's story, and encourages him to find another member of the Brotherhood to stand with him against the society. Patterson convinces Philip Dunning (Robert Pine), the new initiate, to become his ally.