Oxford University has a long time wish to make a dictionary of the English language, but the project keeps stranding. At last they hire the outsider James Murray played by Mel Gibson.
Murray has no university degree. He is a self-taught expert in a stunning amount of languages. After some doubt, he can start is the project. He has some unconventional ideas. Instead of reading everything available in the English language to distill words, definitions and thus the development of the meaning of the word, he wants to use the general public to mail cards with words, meaning and sources so they can catalogue and cross-check them.
One of the volunteers is William Minor (Sean Penn), convicted for shooting a man, a mad, but otherwise brilliant man, with a lot of time on his hands.
The story may sound a bit dull, but actually the film is a very well done drama with an interesting story and good acting.