Cornwall, 1783. Ross Poldark returns from the battlefield to find his father dead.

Ross plans to reopen his family mine with Francis. Demelza struggles to fit in at Nampara.

News of Ross and Demelza's marriage spreads, damaging Wheal Leisure's prospects.

Demelza gives birth. Ross welcomes old friend Dr Dwight Enys to Cornwall.

George expands the Warleggan empire, launching a new ship and bankrupting Carnmore.

Ross prepares for his trial as Demelza and Elizabeth try to help his cause. George does everything in his power to harm Ross, Francis wrestles with his conscience, and Dwight clashes with an entitled heiress, Caroline Penvenen.

Ross and Demelza face financial ruin, and George plans revenge on Jud. Francis, meanwhile, tries to rebuild his life and extends an invitation to Ross and Demelza.

Needing money to open a mine free of George's influence, Ross strikes a deal with a local smuggler. Dwight, meanwhile, tries to diagnose an epidemic and receives help from an anonymous benefactor.

An informant in the smuggling ring poses a serious threat to all, and George buys Ross's debt to finally crush him. Meanwhile, Caroline returns to Cornwall to make an announcement, but it is Elizabeth who reveals a great secret.

Ross tries to help Francis's family financially, but George calls in Ross's debt. Demelza toils loyally to protect all at Nampara, and Dwight and Caroline continue to meet in secret.

Dwight enlists in the navy to forget Caroline, and Demelza visits Verity to spend some time apart from Ross. While Ross considers rejoining his regiment, Elizabeth and George settle into married life, but George's plans provoke the locals to riot.

Ross and Demelza look to forget the past and rebuild their marriage, but new arrivals threaten their fragile reconciliation.

George pursues a vacant seat in Parliament as Agatha plans for her hundredth birthday, and Ross is given a proposition. Meanwhile, there is a new arrival at the Whitworth vicarage.

Ross is adamant George will lose in the election and determines to get a headstone made for Agatha's grave, something Trenwith has neglected. George, meanwhile, questions Dwight over Valentine's legitimacy and - paranoid and jealous - shuts himself to Elizabeth, as Rowella begins to seduce Osborne Whitworth and Demelza receives tokens of Hugh's affection. Sam continues to pine after Emma, as Dwight instructs Osborne to forego intercourse with Morwenna and Cary informs Lord Falmouth that the Warleggans will be opposing Falmouth in the election. Ross returns from his mine to discover Hugh Armitage at Nampara with Demelza - and this time Hugh's attention does not go unnoticed..

The Poldarks determine to get their relationship on track and the Enyses announce they're expecting a baby. Hugh's worsening health threatens his chance to stand in the election, and the prospect of him remaining in Cornwall adds pressure to the Poldarks' fragile marriage. At the Sawle Feast, Tom Harry challenges Sam to a wrestling match. When Emma offers herself as the prize, Sam accepts.

Ross faces the challenge of Parliament and the Warleggans refuse to accept defeat. In Cornwall, Demelza contends with a failing mine and fixing Drake's broken heart. Dwight and Caroline welcome a baby daughter. Ossie meanwhile tends to a dying parishioner and George hosts an extravagant party at Trenwith.

After it is revealed that Nathaniel Pearce embezzled Pascoe’s client’s funds, the Warleggans take action. In London, Ross finds Geoffrey Charles led astray by Adderley. Sam convinces Drake to return from exile following his abandonment of Rosina and Morwenna’s subsequent rejection and Morwenna reveals some news. Dwight meanwhile helps in the development of Truro’s infirmary.

Ralph seeks to ruin Ned as rebellion stirs and the Poldarks are trapped in the middle.

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