Salem can be fun, but it often lets its plot meander in favor of big, bloody spectacles. But now that Cotton Mather's father, the fearsome Puritan minister Increase, is in town, these witch trials are finally starting to get interesting.
Increase's presence in Salem has two immediate effects: First off, it disrupts Cotton's life. Increase doesn't approve of his precious child drinking and whoring, and wants to free him from temptation so that he can become the governor of the colony someday.
Salem has largely been about the battle for the soul of America. On the one hand, we have the witches who serve the Devil and on the other, we have the Puritans, who claim to be righteous but whose cultural strangles the lively people who stand in the middle, people like Cotton, John Alden, and Anne Hale. In a lot of ways, Cotton represents a sort of promise of America, a person who can free the country from supernatural forces through science and other forms of knowledge. But Increase may very well poison Cotton's soul and turn him into the person who will destroy his neighbors' lives with suspicion and despair.
After Increase discovers that the madam of the local brothel is a witch, the madam names (after several torturous dunks) Cotton's beloved Gloriana as a fellow practitioner of the dark arts. Increase seems delighted to investigate Gloriana's potential witchiness, even forcing Cotton to submit her to the humiliation of an inspection of witch marks. After John Alden tries to sway Increase with a reminder that he can love his son while hating his son's decision (his own version of "hate the sin but love the sinner"), Increase decides that he will forcibly remove sin—and decision-making—from Cotton's life. He acquits Gloriana of witchcraft, but banishes her for her sexual "crimes." Without Gloriana to temper Cotton, Salem may become an even more dangerous place to live.
In the meantime, Mary Sibley is also quite perturbed by Increase's presence. She figures that it's only a matter of time before Increase realizes that her husband, George, is not sick but bewitched, and asks Isaac to take him to a hospital in Boston. Desperate, George cuts the toad familiar from his belly, which frees him from Mary's spell but also leaves him with a gaping, deadly wound—and only Isaac, the man he literally branded as a fornicator, can save him. George figures that he's a rich enough man to buy Isaac's cooperation, a move that could have gotten him killed. It's only Increase's natural suspicion and Isaac's discomfort with lying to the minister that ensures George ends up in Increase and not Mary's hands.
With George in Increase's care and now under a very temporary spell that keeps him from talking, Mary now has a problem to solve that is much more interesting than the witch-on-witch war that consumed so many of the early episodes. Pull up a chair, Increase Mather. We're happy to have you stay.