Poldark, from WGBH's Masterpiece , is in its fourth season of romance, drama and action-packed episodes. Aidan Turner stars as the roguish Ross Poldark and Eleanor Tomlinson plays his fiery partner, Demelza. In tonight's episode Ross faces successive failures in Westminster and, to his frustration, he is advised to take a slyer approach. Back in Cornwall, Demelza continues her matchmaking efforts.

Watch it tonight at 9pm on WGBH 2.