The story begins from where The Adventures of Tom Sawyer left off. Huckleberry’s adventures with Tom Sawyer had seen his fortunes grow from abject poverty to instant riches, after they found a stash of gold belonging to a robber. The Adventures of Huckleberry Finn is thus set in St. Petersburg, Missouri, just like its predecessor.
The narrator, Huck reveals how he got six thousand worth of gold after equally splitting the robber’s loot with Tom Sawyer. Huck invested his money with Judge Thatcher and he is earning an interest of a dollar for each gold. He lives with two sisters, Widow Douglas and Miss Watson, who are trying to “civilize” him. Huck is however not fond of the civilization, which essentially means being taught good manners, cleanliness, education and religion. He misses his old treacherous ways and elopes to meet his friend Tom.
Tom however warns him that he must stay with the old sisters and learn to be respectable, if he wants to join his robbers’ gang. Huck obliges and continues to live with Miss Watson and Widow Douglas, until Tom comes over and sneaks him out to go and form the robbers’ gang. The gang is however disbanded due to lack of adventure. Things turn for the worst for Huck when his drunken and brutish father, Pap shows up and demands for his money.
Pap is however not able to get Huck’s money from Judge Thatcher. He then goes to a legal battle against Widow Douglas and Judge Thatcher to regain custody of his son. He successfully wins the sympathy of a new judge, who claims that he does not want to separate a child from his father. After getting jailed severally, Pap is given accommodation by the new judge who believes that he can change him. He soon realizes he made a mistake when Pap sneaks out of his house twice in the same night to trade his clothes for whisky and subsequently breaks his left arm.
After getting kicked out of the judge’s house, Pap lives a drunken life for several months. During this time, he constantly harasses his son to try and discourage him from going to school. Huck nonetheless goes to school to spite him and is even improving in reading and is warming up to the widow’s ways. This angers Pap and he spends more time at the widow’s place. The widow cautions him to stay away from her house. Pap responds by kidnapping Huck and holds him captive in a cabin hidden in the woods across the Illinois shore.
For several months, Pap would go to the store, trade game and fish for whisky. He would go back to the cabin where he locked Huck and physically abuse him. The beatings get worse and Huck, fearing for his life, hatches a plan to fake his death. He kills a pig and spreads its blood all over the cabin. Escaping with a canoe, Huck ends up at Jackson’s island, where he hides as townspeople search for him. At the island, he also encounters Jim, Miss Watson’s slave. Jim has eloped from his master after he eavesdropped on Miss Watson’s plan to sell him to a plantation.
Huck teams up with Jim and they hide out in the island. As Jim predicts, a huge storm hits the island, which causes the Mississippi river to flood. They come across a drifting house and decide to loot it. Inside the house is the body of a man who has been shot dead. Jim prevents Huck from seeing the face of the dead man and tricks him into believing that it would bring bad luck. Everything goes well on the island, until Huck, who is disguised as a girl learns from a woman that her husband had discovered their whereabouts and together with a friend was headed to the island. He also learns that a $300 reward was placed on Jim’s capture.
Huck alerts Jim and they head down the river with a raft. After several days, they pass St. Louis and stumble upon a crippled steamboat. They decide to explore the steamboat and manage to run away with the robbers’ loot. Things do not go as they planned when they miss the intended stop at the mouth of Ohio, due to a night of thick fog. At the shore, they come across a group of men looking for runaway slaves. Huck struggles with his conscience to either sell out Jim or conceal his identity. He eventually decides to help his companion by lying to them that his father, who is on the raft is suffering from smallpox. The men give Huck money and rush away, terrified of the disease.
The two continue with their journey downstream, after they realize they have passed their intended stop at Cairo. However, their raft is dismembered into two by a steamboat, which leads to their separation. Huck ends up at a prominent family known as the Grangerford. He learns of the family feud his hosts have against the Shepherdsons, another aristocratic family. The feud escalates to violence when Sophia Grangerford elopes with Harney Shepherdson. This results to many casualties for both families, including Buck Shepherdson. Huck decides to run away after locating Jim, who has rebuilt the raft.
Two days later, they encounter two con artists who pretend to be the Duke of Bridgewater and the Dauphin-heir to the French throne. The two con artists join Huck and Jim and on their journey, pulling a series of scams in the process. During their scouting expeditions, they encounter a boy who informs them of the demise of Peter Wilks, who has left all of his inheritance to his two brothers in England. The duke and the dauphin decide to disguise themselves as Harvey and William Wilks in order to secure the inheritance.
The two con artists successfully convince peter Wilks’ daughters and the whole townspeople that they are indeed the deceased’s brothers. As a result, they both get a share of the inheritance. Huck however grows fond of the deceased’s daughters and hatches a plan to save them from the two con men. He locates where the duke and the dauphin have safely hidden the gold and hides it himself, awaiting the right opportunity to hand it back to Peter Wilks’ daughters.
Huck is forced to reveal to Mary Jane about the whole plan to con them of the inheritance. He also reveals to her where he stashed the gold. Although Mary is angered, she does not create a scene as per Huck’s wishes. Tensions rise high when two strangers show up in the town and claim to be the Wilks’ brothers, Harvey and William. The older of the two gentlemen familiarizes himself as Harvey. The dauphin laughs it off and they go to a verbal confrontation with the gentleman.
They both claim they know what is tattooed on the dead man’s chest. The dauphin says it is an arrow, while the gentleman says it is a blurred P and B. In order to prove each man’s claims, they must exhume Peter’s body from the ground. They soon discover the hidden gold in the coffin, which sends the crowd into frenzy. Huck manages to sneak away and together with Jim they embark on their journey. Unfortunately, the duke and the dauphin have successfully escaped too. Huck and Jim are forced to accommodate them on their raft again. The two conmen suspect each other of stealing the gold. They however rekindle their friendship after getting drunk and begin plotting against new villages.
Their fraudulent schemes do not bring enough money however and the two men decide to sell Jim for a $40 reward. Huck grows furious when he stumbles upon a fake handbill, which promoted the sale of his friend and vows to help Jim - even if it meant going to hell. Huck traces Jim to the Phelps farm. While there, Aunt Sally and her husband unknowingly think that Huck is Tom Sawyer. Huck plays along and answers questions regarding Tom’s family. On his way to town, he stumbles upon Tom Sawyer who promises him to help him save Jim. Tom pretends to be his younger brother, Sid Sawyer.
Huck and tom discover a small farm cabin where Jim is being held. Huck comes up with logical plans to save Jim. However, Tom rejects them for being too simple. Tom on the other hand formulates unrealistic rescue plans that look exactly like what he had read from the novels. Using his imaginative mind, Tom sets to build the ideal prison in order for Jim to escape. This includes putting spiders, rats and snakes into Jim’s cabin. He then stupidly alerts the Phelps family of an impending escape plan at the cabin.
Huck discovers that the Phelps have sought the assistance of 15 men to quell the escaping attempt. He slips out to alert Tom and together with Jim, they escape to the river. Once they reach the raft, they are shocked to learn that Tom has been shot. Although Tom urges them to go, Jim refuses to leave until a doctor attends to Tom. Huck finds a doctor. He is however left behind because the canoe cannot carry the four of them.
When Tom, the doctor and Jim arrive at the Phelps farm, Jim is put into bondage and the men have a hard time deciding what to do with him. Tom however narrates to them how he and Huck orchestrated the whole escape. He then reveals that Miss Watson set Jim free in her will when she died. Eventually, Huck and Tom are forced to reveal their true identities after Aunt Polly shows up. Aunt Sally offers to adopt and ‘civilize’ Huck, but he declines and announces his plans to venture to the west.