It's back: Series 4 of Vienna Blood set to screen on BBC2 on Sunday evening

Following hot on the heels of The Turkish Detective, the channel is airing another crime drama set against the backdrop of a foreign city with the first of two feature-length episodes of Vienna Blood.

If you missed the previous three series, which are based on the Liebermann novels by Frank Tallis, it’s set in Austria in the first decade of the 20th century.

Matthew Beard stars as Max Liebermann, a doctor and student of Sigmund Freud, who teams up with Police Detective Oskar Rheinhardt (Juergen Maurer) to bring a psychological insight to the cases. As Matthew explains, their relationship has evolved over the course of the drama.

He says: “In the first season there was a conflict between Max and Oskar. Max believes passionately in this very new science of psychoanalysis and has strengthened himself knowing that he’s going to face a lot of boundaries in trying to push this science forward. And Oskar is very uninterested in the world of the mind. They’re starkly different at the beginning.

“And then they start to respect each other’s opinions, see each other’s nuances and begin to see the grey areas in life rather than being so black and white about things. They grow tight as a friendship and that makes both of them mature as people.”

The actor, whose other credits include Funny Woman and Magpie Murders, continues: “Then in the second series that friendship really develops, and they become a great team using each other’s strengths. And in the third season a new layer of conflict emerges.”

But where do we find them as they embark on their latest case?

Well, it’s now 1909, and Max has recently returned from of a tour of the US when Inspector Rheinhardt asks for help in what could be the biggest case of their careers. It turns out that there’s been a double murder – and the victims were the Director of a Security and an arms dealer who was in police custody at the time.

As they learn more, Oskar and Max discover a conspiracy that leads to the heart of government, and realise that the future of the Austro-Hungarian empire could be at stake.

Speaking ahead of the third series, Matthew said: “I’ve never done anything like this before where I’ve revisited a character over such a long period of time, so it’s been really interesting to meet Max again every year.

“I think the most wonderful thing about Vienna Blood is returning to work with the same colleagues again. So, for example, the relationship I have with Juergen who plays Oskar, I’ve never had with any actor, ever in my life. Because I’ve never worked with someone for that long.”

So, if the hints that this could be the duo’s final case are correct, it will be bittersweet – but at least they are going out with a juicy storyline.