Tom Sawyer and Becky Thatcher get lost in a cave during their school field trip. Their teacher and the other pupils don't even miss them and leave them behind. Back in St. Petersburg the schoolteacher finds out that there are two pupils missing. Constable Moeller starts a search party. Meanwhile in the cave Tom has an encounter with Injun Joe and he and Becky run away.The two find an unknown exit out of the cave. Judge Thatcher gives order to shut the entrance of the cave. When Tom hears this, he tells him that Injun Joe could well possibly still be in the cave