The climax of this moving and incredibly powerful book undoubtedly comes in Chapter 19, when Kit is tried for supposedly being a witch. When we look back at the rising action, however, we see that there are a number of different events of sequences of events that have led to this point, known as the rising action in terms of the plot.
Firstly, and centrally, the friendship between Kit and Hannah Tupper, who is shunned, isolated and ostracised by the rest of the townsfolk, is key to this development. It is the friendship that results in Kit bringing Prudence to Hannah's house for her reading lessons and above all it is the love that Kit has for Hannah that impels her to go to Hannah's house and help her flee before the enraged mob burn her house down and potentially do something terrible to Hannah herself. Kit repeatedly disobeys her Uncle Matthew's instructions to not go to Hannah's house, thus casting suspicion on herself, as Hannah is thought to practice witchery by the townspeople.
Secondly, the fever that strikes the town is another crucial element that leads to Kit's arrest and trial. Kit herself is sick, but only fleetingly, and recovers soon, able to help others back to health. However, the swiftness of Kit's recovery combined with her friendship with Hannah Tupper appears to be another piece of evidence that suggests that Kit is a witch, or at least in league with one.
Thus Kit's friendship with Hannah and the way that she recovered from the fever so quickly automatically makes her a suspect to the frenzied townsfolk who are eager to find a victim, especially as Hannah Tupper managed to elude their trap. It is this that leads to Kit's arrest and trial and the climax of this novel.