FAIR City teenager Dearbhla sees her dad kissing his former mistress Jo on Facebook.
The schoolgirl is shocked when somebody sends the picture anonymously to her Facebook account.
Curious Dearbhla opens it -- and is shocked to see her father Tommy passionately kissing Jo during their recent tryst at the National Ploughing Championships.
The student opens the image while sitting across from her parents, Tommy and Judith snuggling up together, relieved that Judith has been given the all-clear from her recent cancer scare.
And while his shocked youngest daughter is studying the image to see for sure it's her father cuddling up to Jo, Tommy is assuring his doctor wife Judith that he will look after her from now on.
It soon emerges that a former school friend of Dearbhla posted the picture to her on Facebook -- and it has shocked the teenager to the core.
"Dearbhla is the quiet and studious one of the family," said Kerrie O'Sullivan who plays her.
"She is also very protective of her family and is shocked to receive this photo. It is a lot to take in for someone her age. Will she confide in her sister, or mom and Dad? Or will she let it slide in the hope that the image is not what it seems."
"Judith's cancer scare has made Tommy realise how much he loves Judith. This has been a big wake up call," said Geoff Minogue who plays the love cheat Tommy.
"He thinks that he has been so clever with his affair with Jo. He has put it behind him now and wants to build a relationship with Judith again. Will he get away with it? Or will Dearbhla spill the beans?"
One way or another Judith will definitely find out.
And viewers won't be surprised when it emerges that this isn't the first time that Tommy has been unfaithful to her.