The title character and protagonist of the novel is a 19th century American named Hank Morgan who finds himself transported back in time to 6th century England, where he meets King Arthur and other famous legendary figures. King Arthur's times are depicted in the novel as being times of ignorance and danger in which life was extremely harsh for ordinary people. The main villain of the novel is Merlin, a very different character from the version of the magician who appears in T.H. White's The Once and Future King. The Merlin of Twain's novel represents the old order which wants people to continue to believe in magic and superstition and seeks to prevent scientific advancement.