Irwin "Fletch" Fletcher is an investigative journalist working undercover on a beach to expose drug dealing. While pretending to be a bum, he is approached by wealthy executive Alan Stanwyk who offers Fletch $50,000 to murder him, claiming he has terminal cancer and wants to avoid a slow death. Sensing a bigger story, Fletch agrees to the proposal but decides to investigate Stanwyk's background and motives. Fletch's investigation leads him to use multiple disguises and personas, each revealing more clues about Stanwyk's true plans and connections.

As Fletch digs deeper, he discovers links to police corruption and corporate fraud that extend beyond Stanwyk's initial offer. His inquiries make him a target, causing tension with his editor, involvement with a suspicious colleague, and run-ins with corrupt cops. His charm, wit, and resourcefulness allow him to navigate this dangerous maze, concealing his real identity while piecing the puzzle together. The plot thickens as Fletch unearths a web of lies and deceit, pushing him closer to uncovering a conspiracy far larger than he imagined.