Flesh and Blood: Mark and Mary come face to face for tense scene in Wednesday's penultimate episode

Flesh and Blood on ITV has kept viewers hooked all week. The thriller, which stars Imelda Staunton and Russell Tovey, centres on Vivien (Francesca Annis), her children and new partner Mark (Stephen Rea). Since the first episode, viewers of the show have been convinced that Imelda's character Mary and Stephen's character Mark have something to do with the mysterious incident that has resulted in the near-fatality of an unknown person.

And, in Wednesday's episode, the two shifty characters come face to face for a tense conversation for the first time. In a first-look clip released on ITV's Twitter, Mark can be seen tending to the garden, as their neighbour Mary approaches him. "Just smartening the place up a bit for when the estate agents arrive, first impressions are very important," explains Mark. The tension rises even further when Mary then subtly assures him that she doesn't plan on leaving them alone. Mary states with a wry smile: "And don't worry about me because I can always get in the front." Could Mary be behind the incident after all?

MORE: Where is Flesh and Blood filmed? Inside the shooting locations for new ITV drama

imelda flesh and blood
imelda flesh and blood

Could Mary be behind the mysterious crime?

In the first two episodes, viewers saw Mary, a long-time friend and neighbour of Vivien, grow more and more suspicious of Mark after his and Vivien's relationship escalated very quickly into marriage and selling the house. Vivien's three children (Russell Tovey, Claudie Blakley, and Lydia Leonard) are also highly suspicious of their mum's new partner, and viewers at home are also convinced that Mark could be the one behind the mystery crime.

MORE: Flesh and Blood: viewers already have a theory on the plot of new ITV drama

stephen rea
stephen rea

Many viewers think Mark is the culprit

One person took the social media to voice their theory: "[Mark]'s not really a doctor. Giving her drugs to make her feel she's ill and running out of time so he can marry her and get her money." Another, however, isn't as convinced: "Why are they lining up the new guy as a Dr Death... #FleshAndBlood too easy right?" We'll have to wait and see to find out!

Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.