Petersburg, that "sleepy little village" we read about in The Adventures of Tom Sawyer, awakes to the news of Huckleberry Finn's presumed murder, and the escape of Miss Watson's Jim. A confrontation is evoked between Jimmy Finn, and Judge Thatcher, when widow Douglas is given the rights to Huck's money. Jimmy swears revenge against Judge Thatcher, and nearly kills Widow Douglas.

Without Huck, Tom Sawyer turns his attention to Becky Thatcher as his new bosom friend. She proves to be a willing comrade and participant. The two embark on an expedition of an old home-The Stantan Home-to look for a rumored treasure. They discover a passageway that has been filled with dirt. Believing the treasure to be on the other side, they begin removing dirt. Their adventure is interrupted when Jimmy takes out his revenge on Judge Thatcher by kidnapping Becky, with the help of two accomplices. Becky knows she must remain strong in order to overcome her ordeal. Tom, believing he is to blame for her kidnapping, goes in search for her.

After Becky's escape, she and Tom resume their adventure within the Stantan Home. What they discover at the end of the tunnel both amazes and mystifies them. And it has nothing to do with the rumored treasure!