A plea for help from Ross’ old Army Colonel, Ned Despard, disturbs the Poldarks’ newfound peace. Demelza manages their affairs in Cornwall but encounters a new opponent. George struggles to engage with the world after Elizabeth’s death.
Demelza and the children join Ross in London, but his dogged pursuit to help Ned finds them caught in a dangerous web. George’s lingering grief has unexpected consequences, while Dwight’s expertise and honorable intentions place him and his friends on shaky ground.
Ross’ mission to help Ned bears fruit, but not without cost. Demelza wrestles with how best to help the community, and Morwenna finds hope. A new relationship continues to blossom, while George’s sanity continues to deteriorate.
Ross receives hopeful news and Dwight gains unexpected patients. Morwenna keeps a secret from Drake, and Geoffrey Charles and Cecily discover the devastating truth of Ralph and Cary’s plan.
Ross returns to London in the hope of securing his friends’ passage home and Drake takes a bold risk to help Morwenna. Geoffrey Charles and Cecily find themselves in trouble, while George and his allies hatch a plan to destroy their opposition for good.
Ross seeks vengeance in London, while Demelza discovers the identities of the smugglers. Caroline puts her insecurities aside to help a friend, drawing perilous attention to herself in turn.
Several months have passed. With their lives on the line, Ross and his friends must launch their most daring plan yet, to save themselves and the country from enemies both at home and abroad.