Charlotte threatens to uncover Kerri-Ann and Mondo's affair on Fair City, take a look at this exclusive sneak peek of the next episode from Carrigstown here.
Kerri-Ann agrees to throw Charlotte a surprise birthday party but it all goes horribly wrong when a hostile Charlotte commands the attention of all the guests and starts to praise her brother Decco.
"A special thanks to my bro, Decco", she said. "You're always there for me, and I want to do the same for you.
"I have a surprise for you," she continued. "I know how much you love your wife, Kerri-Ann."
"With all my heart", he responds, kissing Kerri-Ann on the cheek.
"Well, you'll never believe what her and Mondo have been up to behind your back", Charlotte says spitefully.
"Alright, what have you two been hiding from me?, an oblivious Decco asks, as look Charlotte looks smug.
Fair City continues at 8pm on Thursday on RTÉ One.
Catch up on Fair City on the RTÉ Player.