The family have turbulent times ahead over the next few weeks as Mercedes (Jennifer Metcalfe) lets her life spiral out of control, with devastating consequences for her loved ones.
Seeing how much Mercedes is missing her ex-fiancé Riley Costello (Rob Norbury) and their baby son Bobby, Cooper's character Jacqui decides to make contact with the footballer.
However, while Jacqui is away visiting Riley, Mercedes hits a new low by trying to kiss her sister's husband Rhys (Andrew Moss).
Cooper told Soaplife: "Jacqui knows something has to be done, and she's going to try and get Bobby back. She asks Rhys to keep Mercy company while she's gone."
Discussing the kiss, she continued: "Rhys tells Jacqui himself. He was horrified it happened. Jacqui goes round to the McQueens' house and has a massive argument with Mercy. She goes through all the things Mercy's done wrong in the past. In fact, all the McQueens join in - even Carmel.
"Mercy [then] reveals a dreadful secret. I can't say what it is. The McQueens are at breaking point, but this revelation brings the family back together."
Cooper added that viewers should not rule out a reunion for Mercedes and Riley.
She said: "There could be a second chance there for her and him."
Hollyoaks airs weeknights at 6.30pm on Channel 4 with a first look screening at 7pm on E4.
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