As Demelza manages their affairs in Cornwall she encounters disenchantment and a new opponent, Tess. George meanwhile struggles to engage with the world after Elizabeth's death and it falls to Cary to expand the family empire - as Valentine struggles to find his place within it.
Arriving in London, Ross finds a city gripped with paranoia, and is determined to save Ned from the conspiracy that imprisoned him. George enters into an alliance with the merchant behind Ned's imprisonment, Ralph Hanson, whose business is in upholding the slave trade. Meanwhile, Geoffrey Charles decides to follow in Ross's footsteps and enter the military - but also finds himself drawn to Cecily Hanson, Ralph's daughter.
As George's grief leads the Warleggans into uncharted and worrying territory, Ross discovers a grave plot and is urged to heroism, while Demelza is forced into action herself back at home.