George's cabal moves to ruin the Poldarks, and Morwenna wrestles with a heavy decision.

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. Sam continues to meet with Tess against all caution as Cecily and Geoffrey Charles plan their escape with Ross's help, but the danger that stalks the Poldarks follows swiftly.