In chapter nine Huck and Jim went exploring and found a cavern to stay in, so they moved all of the supplies. One night they saw a dilapidated house boat floating by, so they climbed aboard to inspect it. It was empty except for a dead man that Jim found, whom he covered with a blanket so that Huck wouldn't have to look at him. They took some supplies, including various clothes and a quilt. When traveling in the canoe during the daytime, Huck decides that Jim should lie down and cover himself with a blanket because he didn't want to answer questions about why he is traveling with a slave.

Chapter ten opens with Huck and Jim finding eight dollars in silver sewn into the lining of one of the coats that they found on the houseboat. Huck mentions that this money seems to be a sign of good luck even though Jim told him that when he touched a snakeskin the other day that it would bring them bad luck. A few days later Huck finds a rattlesnake in their cavern, so he kills it. Then as a joke he puts it on Jim's blanket. When Jim returns and sits on the blanket, the snake's mate had curled up around the dead snake, so it bit Jim. Jim begins to drink a bunch of whiskey, and Huck feels terrible that the bite is all his fault although he says nothing about it to Jim. After eating a piece of the snake and waiting a few days for the swelling to go down in his foot, Jim starts to feel better. They decide that Huck should try to find out what people are saying about Jim and Huck both being gone, so Huck dresses up as a girl and finds a cabin across the river where he can talk to the woman living there to find out what she knows.

In chapter eleven, Huck struggles to remember that he's supposed to be pretending he's a girl. The woman asks him a lot of questions and she tells him some rumors going around about how some people think Pap killed Huck while others believe maybe Jim did it. There's a reward out for both Pap and Jim. The woman then mentions that she's seen smoke on Jackson's Island, so she's planning to have her husband go check it out in case Pap or Jim is hiding there. Then she asks Huck to thread a needle, catch a lump of lead, and try to hit a rat. These tests help her to realize that Huck is not a girl as he was pretending to be, so he admits that he's a runaway, and she lets him go. Huck then races back to the island to tell Jim that they must leave immediately.

In chapter twelve they set out on the raft. Jim creates a wigwam for them to stay under to avoid inclement weather or being seen. After a few days, they pass St. Louis, Missouri. Along the way they steal fruit and other things to eat. Then they come across a steamboat that had crashed. Huck sneaks on and finds two robbers threatening to kill a third man. Hidden away, Huck listens as they decide to leave this man to die on the sinking steamboat instead of killing him outright. Huck then runs to tell Jim that they need to steal the men's life boat so that all three of them are stuck on the steamboat. However, Jim reveals that while they were both sneaking around the steamboat, their own raft floated away.

Huck and Jim reveal more of their superstitions in these chapters. They also show how well they get along when it's just the two of them. Jim begins to emerge as a father-figure to Huck in the way that he watches out for him, not wanting him to look at the dead man or creating a wigwam to protect him from the rain. They are surprised that the town believes Jim would murder Huck because both of them have an altruistic nature where they try to do the right things.