Act One

The curtain rises on Tom Sawyer, happily fishing in a meadow outside of St. Petersburg, Missouri, in 1840. When his friends arrive, as the obvious leader, Tom joins them in a game of Robin Hood. Tom's strict, but kindly, Aunt Polly sends him off to school, where he tricks the schoolmaster, Mr. Dobbins, into letting the class have the day off. Aunt Polly, Mr. Dobbins and the preacher, Reverend Sprague, lament what a rascal he is, but they will try their best with him all the same ("Hey, Tom Sawyer").

The next morning, Aunt Polly orders Tom to whitewash the fence in front of their house. Tom's half-brother, Sid, an insufferable goody-goody, couldn't be happier about Tom's punishment. Frustrated, Tom plans to run away someday and have adventures ("Here's My Plan"). As Tom procrastinates, Becky Thatcher, a beautiful newcomer to St. Petersburg, walks past his house. They're instantly attracted to each other. She is Judge Thatcher's only daughter, and, when he and Aunt Polly establish that they are both raising children alone, they bond. Then, Tom's best friend in the world arrives: Huckleberry Finn, the town outcast. When Huck comments that painting the fence looks like fun, Tom gets an idea. Moments later, Tom tricks his schoolmates into painting the fence for him... and gets them to pay him for the privilege ("Smart Like That")!

That night, Tom and Huck go on an adventure and visit the local graveyard. Huck has told Tom that he can get rid of warts by swinging a cat in a graveyard. Hidden behind a gravestone, the boys see the troublemaking Ol' Man Joe, Doc Robinson and a local vagrant known as Muff Potter, digging up a grave. Ol' Man Joe and Doc Robinson get in a fight over how much Doc is paying them ("Hands All Clean"). In the fight, Muff gets knocked unconscious. Ol' Man Joe murders Doc Robinson with Muff's knife, and Tom and Huck have witnessed the entire thing.

The boys run off. Tom wants to tell someone, but Huck convinces him that Ol' Man Joe will come after them if they do. They swear in blood to keep mum forever about the bloody deed ("The Vow"). Meanwhile, Ol' Man Joe convinces Muff that he killed Doc, and Ol' Man Joe agrees to help Muff in exchange for half of Murrell's gold. Muff has a treasure map leading to the gold and agrees.

The next morning, on the way to church, Aunt Polly and Judge Thatcher, both single parents, commiserate about raising children on their own ("Raising a Child"). Later that day, in church, Tom tries to impress Becky Thatcher by tricking Reverend Sprague into awarding him the coveted Bible Prize, much to Sid's dismay ("It's in the Bible").

On the way to school the next day, Tom tries to convince Huck to learn to read, but Huck is afraid. A few minutes later, Huck saves kindly old Widow Douglas from the advances of the town drunk – his father. In gratitude, she offers to teach Huck how to read; she even offers her home as a place to live, but Huck declines ("It Just Ain't Me"). In school that day, Tom saves Becky from getting into trouble. Moments later, they declare their undying love for each other. Tom says that they should become "engaged," and she agrees ("To Hear You Say My Name").

A few days later, Muff Potter is arrested for murder. Muff doesn't realize that Ol' Man Joe has framed him, and he pleads with Joe to save him from hanging. Joe says that he'll help, as long as he gets the gold. Muff gives him the map ("Murrell's Gold"). As Muff is taken to jail, Tom faces a terrible choice: Should he tell the truth about the murder and save Muff Potter, thereby incurring the wrath of Ol' Man Joe? Or should he keep his vow to Huck and let Muff hang ("Murrell's Gold – Reprise")?

At the trial, Ol' Man Joe sells out Muff and testifies that he saw Muff kill Doc Robinson. Then, Tom takes the stand. He tells the truth and swears that Ol' Man Joe committed the murder. Huck, inspired by Tom's honesty, admits that he, too, saw the crime. Ol' Man Joe springs from his seat and threatens Tom. He throws a knife at him before racing from the courtroom amid a hale of gunfire ("The Testimony").

Act Two

A few weeks later, school is dismissed for the summer, and the children and their parents celebrate ("Ain't Life Fine"). Tom, however, is on edge. He cancels his plan to go to the picnic with Becky, and she gets upset with him – threatening to go with Joe Harper instead. They have a fight and end their "engagement." That night, in his bedroom, Tom tells Aunt Polly that he isn't going to the picnic. Aunt Polly assures Tom that Ol' Man Joe is in Mexico and tells him to go to bed; she puts him to sleep with a lullaby ("This Time Tomorrow"). Tom has a terrifying nightmare about Ol' Man Joe, much to Sid's delight. Aunt Polly comforts him and puts him back to bed ("This Time Tomorrow – Reprise").

The next morning, after weeks of secret tutoring by Widow Douglas, Huck at last learns how to read. He and the Widow celebrate ("I Can Read!").

Everyone arrives at the annual town picnic. The festivities begin with the exploration of McDougal's Cave, a cavern of frightening size and darkness. As the townsfolk head for the cave, we learn that Ol' Man Joe is back in town. He, too, is going into the cave to find Murrell's Gold ("Murrell's Gold – Reprise"). Tom and Becky have been paired as cave-exploring partners, much to their chagrin. However, as they explore the caves, they make up. The bell rings for them to go back to the surface, and Tom and Becky realize that they are lost. Aunt Polly and Judge Thatcher are frantic and they begin searching for the two children with the help of the rest of the townspeople ("Angels Lost").

Underground, Tom and Becky desperately try to find a way out of the cave. Becky is very scared, but Tom urges her to stay positive and promises that they'll get out ("Light"). Tom leaves Becky alone for a moment, trying to find a way out; she prays ("Angels Lost – Reprise"). Ol' Man Joe springs from a passage and grabs her, demanding to know where Tom is. Suddenly, Tom jumps out from behind a rock, and Huck shows up a moment later. With great courage, the three friends battle Ol' Man Joe and defeat him. Tom and Becky then find Murrell's Gold, a vast treasure of gold coins. They realize that Huck is badly hurt; this is especially problematic, as Huck is the one who knows the way out. Just then, Tom sees a ray of daylight shining through a crack in the wall. Exhausted, they manage to get Huck to his feet and they all crawl out of the cave, safe at last, with gold in tow.

The next day, the people of St. Petersburg are holding a funeral service for the lost children ("Light – Reprise"). During the service, Tom, Huck and Becky limp into town. They peek into the church – and realize that they're watching their own funeral! They sneak into the church and watch all of the nice things that are being said about them. Reverend Sprague discovers the children in the pew, and the town goes wild with happiness. Aunt Polly is overjoyed to have Tom back, but Sid is not. In the final moments of the show, Huck reveals to Tom that he's learned how to read, and the two friends run off to celebrate with the rest of the town ("Finale").