Yvonne, played by Ciara O'Callaghan, is forced to reveal all to her shocked father Bela about the whereabouts of Stephen, the baby son she had with her former partner Richard.
And Carrigstown stalwart Bela is left disgusted with his daughter when she admits her drug-use led to her son being taken into custody.
The shocking scenes will be screened on RTE One next Sunday -- and viewers will be left wondering whether a seething Bela can forgive troubled daughter Yvonne.
The action kicks off thanks to a row between Yvonne and new love Louie, who believes she has received a gift from a past love.
Yvonne denies it but later the pair decide to go to Vino's to celebrate her father's birthday, although Yvonne tries to dissuade him from attending.
Not surprisingly, the couple start arguing again, much to the irritation of other guests attending the party.
Bela steps in at this stage and ends up in a heated argument with Louie, leading him to make a barbed comment about Louie's past cocaine habit.
Louie decides to up the ante when he drops the bombshell that Yvonne's young son Stephen was taken into care because of her drug habit.
Put on the spot and quizzed about her son's whereabouts, Yvonne is forced to come clean to her devastated father and admits she doesn't know where her son is.
Bela is appalled that his daughter could have neglected his grandson and banishes her from his sight.
After a few hours away, Yvonne tries to return to Vino's, but angry younger sister Suzanne, who already has a fractious relationship with the troubled mum, throws her out. Louie counters that she only has herself to blame as her lying has led to her painful predicament.
Yvonne returns home and has it out with Louie, accusing him of destroying her relationship with her family. Not surprisingly, the couple decide to go their separate ways in an acrimonious split.
She tries to visit her father again to make amends -- but Bela refuses to speak to her.
He later informs his daughter that she has destroyed Stephen's life and her attempts at making the situation right have come too late.
The fall-out from the Doyle's latest row eventually leads Yvonne to seek out Paul Brennan and ask him to act as an arbitrator. Paul was in a relationship with Bela's eldest daughter Helen prior to her death, and uses her memory in encouraging both sides to sit down and talk.
But whether Bela and Suzanne will be able to listen to any more of Yvonne's claims remain to be seen.