The fourth season of the BBC's Poldark culminates on sunday after the feud between the Poldark and Warleggan houses reignited last week. With the doubts over Valentine's true parentage causing rifts in both Ross and George's marriages, the finale promises shocks, drama and an explosive end to the season. Ross' attempts to repair his marriage are ignored by Demelza as she attempts to help Drake and Morwenna find happiness with each other instead. After growing suspicious of Valentine's parentage and his wife's potential infidelity, George's rivalry with Ross reignites as they two houses prepare to go to war again. Poldark - Sunday 9:00pm on BBC1.