In 1876 Ernest Pratt, an imperfect man with vices, is a struggling writer of a series of books based on his popular and fictional character Nicodemus Legend. After being mistaken as Legend, Pratt is enlisted by a helpless group of town folk to once again help them, against a powerful female land owner and the town's sheriff in her pocket.
A well known bank robber name Jimmy Siringo comes to Pratt telling him he's been falsely accused of murdering a bank guard and stealing one million dollars, and wants his help in clearing his name of said charges.
E. C. Allen, the publisher of the Legend book series, orders Pratt to include a new character: Legend junior. And the mother of the young boy makes demands and otherwise causes a nuisance in Pratt's life.