The adventures and misadventures of Tom and Huck on the Mississippi River in Missouri with their involvement when they fall in with a gang of con artists, take up with a ragtag circus, help a freed slave buy his sister's freedom, and then see a dastardly villain get his.
- Set shortly after the ending of The Adventures of Tom Sawyer, Rascals and Robbers begins with St. Petersburg preparing for its 50th anniversary. The church is raising money to purchase a quartet of golden, jewel-encrusted angel statues to mark the occasion. Tom hunts down Huck, whom he finds smoking his corncob pipe in a pickle barrel. Huck is tired of the Widow Douglas trying to civilize him and Tom wants to avoid the town's celebration, which is taking place on his birthday. Tom suggests he and Huck run off to live among the Indians. But the boys are distracted by the arrival in town of the suspicious-looking Scree; Tom suspects Scree is a spy, and he and Huck follow Scree to learn his plans. They overhear Scree plotting with Mr. Clinch, an associate, to ruin the anniversary celebration. When an owl screeches and spooks Tom, the boys are discovered and Scree pursues them. Tom and Huck steal a raft and start down the river, but Scree shoots the rope holding the raft together and Tom and Huck are separated. Tom's half of the raft washes up on shore the next morning and when he goes to seek help, he falls into Scree's clutches. Meanwhile, Huck finds shelter with Jeb and Callie, a hard-luck couple in a run-down cabin. Jeb asks Huck to help him win a high-stakes poker game by hiding in the attic, spying on the table and giving Jeb tips on what cards the other players are holding. Scree shows up to play, with Tom in tow. During a break in the game, Huck rescues Tom, who joins him in the attic. The scheme falls apart when Tom and Huck fall through the ceiling onto the table, creating chaos and setting fire to the cabin. Scree takes Tom and Huck captive and threatens to kill them to ensure their silence, but they narrowly manage to escape and, stealing Scree's horse, they begin their journey home. When Tom complains about his empty stomach, Huck encourages him to have a smoke to take his mind off of it. Tom eagerly puffs on Huck's pipe, but quickly becomes nauseous and woozy, insisting he hears "heavenly music." The music turns out to be coming from Circus Magnificent, a third-rate traveling show run by the hapless magician Arco the Magnificent and his teenage daughter, Alice, who longs for a real home. Tom and Huck join the circus and compete for Alice's attention. They soon meet George, a freed slave from Ohio, who is trying to buy his sister Reba's freedom from arrogant plantation Colonel Beaton, owner of Paradise Plantation. Disguising George as Egyptian royalty descended from the Wise Men, Tom, Huck and George wrangle an invitation to Beaton's birthday dinner at the plantation. Unfortunately, Scree is still trailing Tom and Huck and he arrives just as George's masquerade is exposed. George, Tom and Huck run off with Reba, and head back to St. Petersburg with Arco and Alice. After the group narrowly dodges the gun-toting Scree on the road, Tom leads his friends into MacDougall Cave where they must creep through a cavern swarming with snakes. Reaching the door that seals off the cave, they realize they are trapped: Tom was counting on Arco to open the door with his "magic." Scree attacks, but feisty Alice saves the day when she knocks him unconscious with a rock. Meanwhile, Clinch and his cronies deliver the crated "angels" to St. Petersburg and collect all the money the townspeople have paid for the supposed treasures. Clinch and company hastily leave town, shortly before the crates are opened and the townspeople realize they've bought nothing but a bunch of rocks. Arco uses his flask of whiskey and some fire to blow up the lock to the door and Tom, Huck, George and Arco confront Clinch and the con artists, subdue them and retrieve the satchel full of money stolen from the locals. At Tom's birthday dinner, Tom and Huck complain about the formal clothes they have been forced to wear. Tom catches a glimpse of a pirate strolling along outside the window and tells Huck pirates are even more exciting than spies. As a delegation of grateful residents show up at the dinner to give the recovered money to Arco, George, Alice and Reba, Tom and Huck take advantage of the distraction to slip out the window, off on another adventure.