A poster of BBC TV series "Poldark." Poldark/ Facebook

“Poldark” season 4 may premiere in early summer in the UK, according to a new report. Infidelity will be the main theme of the show this year, and writer Debbie Horsfield has also teased some “utterly tragic” storylines for some characters.

Filming of the fourth season has already been completed, and the show is currently undergoing post-production. According to the Radio Times, lead cast member Aidan Turner (Ross) has said that the show will return “sooner rather than later,” hinting an early summer release in the UK.

What will the plot focus on? Horsfield has teased that the show will explore the reasons why Demelza (Eleanor Tomlinson) cheated on her husband in the previous season. Hugh Armitage (Josh Whitehouse) isn’t going anywhere yet, so there is bound to be a lot of tension in the love triangle. Ross and Demelza will be seen “working through this sticky patch” when the show returns.

Season 3 also teased Ross’ interest in entering politics so he can be in a position to help people. The character will travel to London to take his seat in parliament this year. Meanwhile, Demelza will become more independent in the absence of her husband. She will end up becoming the “boss” of Nampara.

When Ross returns home, he will find his wife becoming his equal in terms of power. It will be interesting to see how the young miner will respond to this development.

In London, new characters will be introduced. Viewers will get to see characters based on real historical figures like Prime Minister William Pitt and anti-slavery campaigner William Wilberforce.

Although the show takes fans to London, it is still very much a Cornwall-based show. Season 4 will also explore how the other characters like Morwenna (Ellise Chappell) and Drake (Harry Richardson) will deal with their problems.