Mercedes recently tore the Costello family apart with her confession that she had cheated on fiancé Riley with his dad Carl. Following her dramatic revelation at the altar on her wedding day, evil Silas (Jeff Rawle) is keen to teach Mercedes a lesson.
Silas's terrible plan is to keep heavily-pregnant Mercedes alive until she has given birth, before adding her to his list of victims. Will it be the end for Mercedes?
Here, Jennifer Metcalfe - who plays Mercedes - has an exclusive chat with Digital Spy about the shock storyline twist.
What was your reaction when you first heard that this big Silas twist was on the way for Mercedes?
"I thought it was brilliant! The writers always come up with great stuff for me, and I'm really privileged and thankful for that. I never doubted that they would come up with another great storyline in the aftermath of the wedding. At the moment, it's brilliant because it's just one great storyline after another for Mercedes, and it's quite flattering to be trusted with things like this."
What goes through Mercedes's mind while she's being held prisoner by Silas?
"Mercedes thinks that she's going to die and she fears that her baby will die too. She's also thinking a lot about Riley and what she did to him. But Mercedes's main mood in the scenes that are coming up is pure fear!"
Mercedes is quite a feisty character too, so will that come into play here or is she too scared for that?
"You'll see her go through different emotions. At some points she's begging, the next minute she's breaking down crying, and then the next she's exhausted. She also tries to do something to Silas and tries to escape, but unfortunately that doesn't work! You'll see Mercedes go through every emotion in this storyline."
Does Mercedes realise that Silas was responsible for the recent murders in the village?
"Yes, it doesn't take long for Mercedes to figure it out. She says, 'Oh my God, you really did kill all those girls, didn't you?'"
Will we see Silas give Mercedes any food and water, or does he leave her to suffer?
"Well, Silas wants to keep the baby alive but not Mercedes. As soon as Mercedes gives birth to the baby, his plan is to kill her! In the meantime, Silas does the bare minimum for her - so he gives her water, a small amount of food and he keeps her reasonably warm too."
The storyline sounds really dark, so would you say Hollyoaks are pushing the boundaries here given the 6.30pm timeslot?
"They are a little bit, yeah. It's all shot in a very clever way, so it was fine when it came to compliance. But it was difficult and there was a lot of stuff that we had to be really careful about when we were filming it."
What was it like to actually film these scenes in Silas's vault?
"Well, they built a set especially for this at the studios - it was right next to The Dog! It looks amazing on screen - it's so good. I was also really lucky when it came to the filming, as I had one day where I was able to shoot five episodes at once, so I was able to get a lot of these scenes out of the way in one go. In total, there were probably about five really long days where it was me tied up in the vault for 12 hours, crying my eyes out!"
Have you been following the Silas storyline yourself as a viewer in the past few months?
"Yeah, when there's a big storyline running like this one, I'll go out of my way to watch the episodes when they're on, or I'll get them on disc afterwards. I think it's quite important to do that, as it helps you to keep up to date with the other characters. Plus, when it comes to your own scenes, you can see how things are working, as your best critic is often yourself."
Have you enjoyed the work that you've been doing with Rob Norbury, who plays Riley, in the past year?
"Yeah, I think we've done some great stuff together and I've really enjoyed the love triangle between Mercedes, Riley and Carl. It's been brilliant working with both Rob and Paul Opacic, who plays Carl."
If Mercedes survives this encounter with Silas, do you think she'd try to win Riley back or would she move on?
"I can't give away what happens, but if she did survive, I think she would want to get him back - definitely."
Some viewers have been hoping that Amy Walsh could return as Jenifique McQueen after appearing in Hollyoaks Later last month. Would you be keen to see her back?
"Yeah, I think she was a great addition to the show. I'm not sure whether there are any plans as I haven't spoken to Amy recently, but we have kept in touch. I suppose there's scope there as Jenifique didn't get killed off or anything like that. I'd love her to come back, as I think she was brilliant. She just fitted in with us all straight away."
The McQueens have had a lot of storylines this year. What do you think the highlights have been for the family?
"I think Claire Cooper's storyline has been really good - the rape storyline with Gilly. I also enjoyed Carmel's storyline with the priest as that was quite light-hearted and fun. Hollie-Jay is back as Michaela now too, and that's brilliant. I also think that Nicole, who plays Myra, has done some of her best work this year - comedy-wise, they've written very well for her. We've all had our own little highlights and it's been a brilliant year."
What are you getting up to outside of Hollyoaks at the moment?
"Well, myself, Claire Cooper and Leah Hackett are about to have a sale of items from our designer dress hire business, The Closet. It's going to be held on November 11 at Dukes 92 in Manchester. Many of the dresses were once worn by celebrities and it should be really fun day!"
> Read more Hollyoaks spoilers and news
Hollyoaks airs weekdays at 6.30pm on Channel 4 and 7pm on E4.