The adventure unfolds as Tom Sawyer and Huck Finn – Tom's friend from the streets – witness a murder in the graveyard. Tom and Huck flee to Jackson's Island and make a pact never to tell anyone about the incident. However, when the good-natured Muff Potter, who has been blamed for the murder, is sentenced to death by hanging, Tom attempts to break Muff out of jail, but it does not go as planned and Muff returns to jail. So Tom breaks his promise and returns to exonerate Muff Potter. Injun Joe, the actual murderer, makes a hasty exit from the courtroom during the trial. A short time later, Tom and Huck find references to a treasure and have to face Injun Joe again.