In next week's episodes of the ITV1 soap, Chas finds a mystery bra at Mill Cottage and realises that Carl (Tom Lister) must be having an affair. After some detective work, she later finds out that Eve is his other woman.
Discussing how Chas reacts to the shock discovery, Pargeter explained: "Her knee-jerk reaction is to confront Carl and Eve. But Charity stops her, telling her she must look at the bigger picture. [Charity says] Chas should go all out to get revenge - Chas eventually agrees.
"She's very hurt but can see the sense in what Charity's saying and she wants to make him pay!"
Meanwhile, asked how Chas plans to get even, the actress replied: "Initially, it's just little things. She can't resist - at the village bonfire, she sticks a toffee apple in Eve's hat when Eve's not looking and all the toffee gets stuck to her hair!
"Next on her list is Carl. She ups her game, sneaks into his office and deletes all the files on his computer. Not surprisingly, Carl's extremely annoyed. But Charity's constantly on at her to up her game and to start playing really dirty."
Suzanne Shaw, who plays Eve, recently revealed that there will be "a big lead-up to Christmas Day" as the love triangle storyline progresses.
> Click here to read full spoilers for next week's Emmerdale episodes