In chapter thirty-three, Huck is heading to town when he runs into Tom Sawyer. Similar to Jim's reaction, Tom first thinks Huck is a ghost. Huck explains what has happened and how he has come to Phelps farm to help steal Jim out of slavery. Tom agrees to help. Huck is stunned that Tom would do something so amoral but very excited to have his help. Tom then has Huck return to the farm ahead of him so that he can play a joke on Aunt Sally. Since they already believe that Huck is Tom, Tom decides to pretend to be his cousin Sid Sawyer.

In chapter thirty-four, Huck and Tom figure out where Jim is being held prisoner. When Huck points out a boarded up window in Jim's cabin and suggests that they pull off the board to help Jim escape, Tom is disappointed. He is sure that they can find a more complicated way to free Jim that will take twice as long. Tom suggests they dig him out. When one of the slaves invites them to take a look at Jim, they go into the cabin, and Jim is thrilled to see them. Then they give the slave some money, so he won't tell anyone.

In chapter thirty-five, Tom continues to come up with more steps they need to take in order to free Jim. He says they must saw the leg off of his bed in order to unchain him although he's prefer that they saw Jim's leg off. Tom also wants to send a rope ladder to Jim in a pie even though Jim won't be climbing down from any windows. Tom gets these ideas from the books he has read. He feels it is the proper way to free someone from imprisonment, and Huck is so happy to have his help that he just goes along with it. Jim must also keep a journal on a shirt using blood or tears mixed with iron-rust as the ink, notwithstanding the fact that Jim doesn't know how to write. Then Huck and Tom steal a couple of case-knives to begin digging with, which Huck decides will take far too long, but Tom feels that It should take them at least a few years minimum if they want to do it properly.

Chapter thirty-six begins with Huck and Tom digging with the knives, and Tom finally admitting it will take far too long, so they agree to switch to picks and just pretend that they're still using the knives. Tom then steals a spoon, a candlestick and some candles to secretly deliver to Jim by putting them in Tom's aunt's or uncle's coat pockets. Part of a candlestick was delivered in Jim's food, and when Jim bit into it, he nearly broke his teeth. Tom and Huck found a lean to that allowed them to sneak into the cabin if they wanted, and some dogs found it and kept creeping in with Jim until they opened the door and tossed out a slab of meat, which the dogs followed, to clear them out.

In these chapters Tom arrives and turns Huck's simple plan for freeing Jim into a convoluted, long-term process. Jim is incredibly kind about all the strange things that Tom is making him do because he's so pleased that these two white boys are willing to help him to gain his freedom. Huck is also quite tolerant of Tom's shenanigans because Tom is his best friend, and Huck is used to his crazy behavior.