When she arrives on the island, Mercedes catches up with half-sister Michaela and cousin Jenifique, before being knocked for six as she comes face-to-face with old flame Johnny, who was the first man to break her heart.
As Mercedes spends time with Johnny, they start reminiscing over the past and sparks fly. With Mercedes still having such strong feelings for her ex, could she be about to stray again?
Digital Spy recently caught up with Jennifer Metcalfe, who plays Mercedes, to hear more about the storyline.
You've appeared in nearly every series of Hollyoaks Later, so is it nice to keep being chosen for it?
"Yeah, definitely! It's brilliant and I'm really flattered. Obviously one of the core storylines is that Mercedes is celebrating her hen night, so I'm really pleased that they've come up with the story and it's been built round us. It's great."
What are the main differences between filming Hollyoaks Later and the regular 6.30pm show?
"You can just push the boundaries a little bit more. It's not too different, though - it's not like we're all swearing all the time or there's loads of sex on screen or anything like that. You can just push it a bit further."
Did you enjoy doing all of the on-location filming in Ibiza?
"It was amazing! We were working out there for seven days and it was just perfect - the ideal place to film and the perfect schedule. We had a lot to fit in so we pretty much worked the whole time."
Mercedes isn't very pleased to be in Ibiza, though…
"Definitely - she's visited Ibiza before and being there just brings back loads of bad memories for her. It's where she met her first love, Johnny, and that really wasn't a good time for Mercedes because of the way things turned out…"
"She sees Johnny there, and it's a real mix of emotions for Mercedes. There's so much stuff that she wants to say to him, but then at the same time she doesn't see the point. There's a lot of anger there. But there's also a lot of excitement for Mercedes as she sees him again, because he was the guy who won her heart for the first time. The storyline also explains why Mercedes is the way she is now."
There's also some trouble from back at home that she has to worry about, isn't there?
"Yes, Mitzeee has put some compromising photos online showing Riley at his stag celebrations. Mitzeee puts those pictures on his Facebook page, so when Mercedes checks the internet on her phone and sees them, she just thinks, 'What the hell is he getting up to?'"
"They do, and it's just them getting lost in the moment, really. You'll see a few moments where they come together - especially after Mercedes gets the pictures through of Riley and she's not sure what he's getting up to, so she has doubt in her mind about her fiancé. There's also a lot of times where Mercedes and Johnny are just talking and reliving the old times, especially how he won her over in the past."
Was it nice to have Hollie-Jay Bowes back as Michaela for the late-night episodes?
"It was great to have her back. Michaela is a little bit different when you first see her in Hollyoaks Later, but that soon changes! And it was really nice to catch up with Hollie-Jay again."
"Yeah, Mercedes doesn't like him very much! He's very stuck up, he doesn't accept the McQueens for what they really are, and he's quite patronising too - which doesn't go down too well. He's a real oddball as well - it's hard to describe, but you'll see what I mean when you watch the episodes!"
Did you enjoy working with Amy Walsh, who's starring in Later as the new McQueen?
"Oh yeah, she's great - she's playing our cousin, Jenifique. She became like a McQueen really quickly and really fitted in with us. Her acting was brilliant too, so she was a really good addition."
Would you ever like to see Mercedes settle down, or do you prefer her love life to be complicated?
"I definitely prefer her when she's complicated! That was my fear when I found out that she was getting pregnant - I don't want her to settle down just yet. I definitely like Mercedes the way she is!"
> Read extra bonus snippets from Hollyoaks star Jennifer Metcalfe in Soap Scoop
Hollyoaks Later returns to E4 on Monday at 10pm. Get the Inside Soap magazine on your iPhone or iPad