Jerry Fletcher (Mel Gibson) is a New York taxi driver who has a unique hobby of creating conspiracy theories. He has an obsession with the government, secret societies, and believes that there is always something sinister going on. He shares his theories with anyone who will listen, including his lawyer Alice Sutton (Julia Roberts), whom he has a crush on.
One day, Jerry's life takes a dangerous turn when one of his theories turns out to be true. He sees a mysterious figure at the scene of a well-known murder of a journalist. As he starts to dig deeper into the case, he realizes that his own life is in danger. He becomes the target of a government agency, led by Dr. Jonas (Patrick Stewart), who are determined to keep their secrets safe.
With the help of Alice, Jerry sets out to uncover the truth and clear his name. But as they dig deeper, they find themselves caught in a web of lies and deceit. They realize that nothing is as it seems, and they don't know who to trust.
As their investigation progresses, Jerry starts to piece together the clues to figure out which of his many conspiracy theories was the one that turned out to be true. It's a race against time as Jerry and Alice try to stay one step ahead of the agency that is determined to silence them. In the end, they uncover a shocking truth that threatens to change the course of history.