The story of the film is adapted from real events. The editorial committee led by Dr. James Murray (played by Mel Gibson) is going to edit a new version of the Oxford English Dictionary. With the human and technological level at that time, it would take a century to complete the compilation of the dictionary. Dr. James Murray pioneered the use of a universal participation method, allowing all English users in the UK to collect definitions for the dictionary and send them to the compilation team by mail. In the process of collecting definitions, they found that a doctor named WC Miner (played by Sean Penn) contributed more than 10,000 quotations alone, which is a workload that is difficult for professional linguists to complete. When the editorial committee decided to pay tribute to him, an astonishing fact was exposed: it turned out that Dr. Miner was a military doctor in the American Civil War. He committed murder because of schizophrenia and was confined to a mental hospital. He was considered a lunatic. A professor and a lunatic, the earliest English dictionary in human history was born in the hands of two very different people.