The narrator chides himself for his didactic digression in the previous chapter. Tom Jones and Partridge travel from Coventry to St. Albans, which Sophia left two hours earlier. Partridge wants to borrow some of Sophia's one hundred pounds—he says that Fortune must have sent it for their use. Jones calls this dishonest. Partridge, garbling some Greek into his speech, says that Tom will understand life better when he grows older. They have offended each other, but Partridge apologizes and Tom forgives him.
A stranger asks to join Jones and Partridge to London. They speak about the dangers of robbery. Partridge alludes to the hundred pounds in Jones's pocket. Near Highgate, the stranger suddenly whips out a pistol and demands the money from Jones. Jones grabs the pistol and restrains the man, who calls for mercy—he says that the gun is not loaded and that this is his first robbery. Partridge, terrified, is still yelling. The man tells Jones that he has five children and a pregnant wife and does not have money to feed them. Jones gives the man a couple of guineas. Partridge says that Jones should have punished the man—stealing deserves death by hanging. Jones reminds him that not long ago Partridge stole some horses.
Book XII is one of the most eventful books of the novel, packed to the brim with the adventures of Tom and Partridge: they discover Sophia's pocket- book, they attend a puppet-show, Tom drinks with Dowling, they attend the Gypsy wedding, and they are almost robbed on the highway. Before the narrator takes us into the courtly realm of London for good, he escalates Tom's ribald road adventures. While the book may seem to jump from one scenario to the next, many of the events are important precursors to Tom's experience in London.
In the final chapter of the book, Fielding distinguishes Tom's sense of honor from Partridge's hypocrisy—the worst characters in the book, including Thwackum, Square, and Blifil, act in contradiction to their words. Partridge's hypocrisy may be excused, however, on account of his pathetic character—he believes the Gypsies to be witches, and he cannot come to Tom's assistance on the highway because he cannot stop yelling. His is thus a less invidious hypocrisy than Blifil's, whose evil is discovered only in the final book of the novel.