In this corner, we have Increase Mather, the torture-loving witch hunter supreme of Salem. And in the other corner, we have a pair of Satan's handmaidens, armed with a cauldron of magical tricks. When they cross blades, who will come out on top?
Now that Tituba has named two witches under Increase Mather's torture—Mercy Lewis, who is a witch, and John Alden, who is not—Increase wants to get all of his diabolical ducks in a row so the trials can begin. Alden isn't a problem; Mather already has him in custody and he's being predictably above-it-all, not even willing to deign the accusation with a denial. You remember what happened to Giles Corey, right John? Refusing to answer the charges is a good way to get yourself killed.
Mercy is a little trickier to nail down. Increase decides to chain up Mercy's fan club and toss ladles of boiling water at them—ever the charmer—in order to get them to talk. When that doesn't work, Mary devises a plan to bring Mercy and Increase together, in the hopes that Mercy will kill Increase. Poor Mercy doesn't see how this would play out; even if she did manage to kill Increase, she'd still probably find herself hanged as a witch, or at least as a murderess. But she doesn't kill Increase and instead dear Isaac the Fornicator ends up with a spike in his gut.
Now Mary has put nearly all of her friends in harm's way: Tituba, Mercy, Isaac. And, as the episode comes to a close, Increase Mather indicates that the only way that John Alden will be freed is if the true witch who converted Mercy steps forward. Mary tells him that anything can happen in Salem—but will she really risk everything for love?
Meanwhile, Anne Hale is dealing with the revelation that her father is a witch. She seeks answers from the still pickled Cotton Mather, trying to figure out what we've been wondering: are witches necessarily evil? It looks like she'll have to figure that one out quickly as her father tells her that she, too, is a natural witch—just as John Alden gets ready to stand trial for witchcraft.