Tensions between Protestants and Catholics escalate when bloodshed at a Protestant service causes an already concerned Mary and Francis to intervene on the eve of Greer's wedding. Bash and Leith lead a search for the guilty that reveals a surprising secret about Castleroy that could destroy his union with Greer. Meanwhile, Francis receives an unwelcome gift from his dead father. Kenna discovers a sex journal, with clues leading to the best lover at court, who just might be a match for Lola.