Brotherhood of the Bell Movie from 1970

While this is a fictional group, the movie depicts the power of secret organizations like the Skull and Bones. Dr. Andrew Patterson (Glenn Ford) learns that an elite society he joined as an undergraduate is really a sinister organization that seizes wealth and power for its members through nefarious practices. After refusing an order from the Brotherhood, Patterson finds himself increasingly isolated, and as he tries to expose the organization he loses his job, wife and more.