A face from John's past comes to Salem, and Mary's plans nearly come apart when she loses control of Mercy Lewis. Elsewhere, Mary's most trusted ally, Tituba, is forced to deceive John in order to eliminate a threat that endangers her mistress.

After successfully capturing Rose, John and Cotton plan to extract information on the Grand Rite from her during the planetary alignment with Saturn. Mary assists Mercy in becoming a witch, and initiates her into the hive.