Tholly takes Ross to a French port where republican soldiers are executing their prisoner. They meet Jacques Clisson, who gives them information about Dwight's incarceration but, threatened with prison himself, Ross returns home without his friend. Banned by Warleggan from using his church, the Carne boys find a venue for their Methodist meeting house, but are again thwarted by Warleggan through a legal loop-hole and are ultimately saved by Demelza, who allows them to use a barn on Ross's land. The Warleggans move to Truro, where even Elizabeth is shocked by the immoral social climbing of her newly appointed magistrate husband, and starts to feel isolated, but their absence leaves Morwenna, encouraged by Aunt Agatha and Geoffrey Charles, to continue meeting Drake.

Demelza discovers the French are smuggling arms into Cornwall, but Ross is determined to take revenge on Merceron and Hanson for framing Ned and returns to London to confront them.

Ross and his friends must launch their most daring plan yet to try to save themselves and the country from enemies both at home and abroad.