Carla was raped by Frank last month and she is currently waiting to see if she will get justice as the evil businessman continues to protest his innocence to the authorities and Weatherfield's residents.
Events take a new twist in this week's episodes as Frank wins his appeal for bail before recruiting his mother Anne (Gwen Taylor) to act on his behalf at Underworld.
King told ITV.com of Carla's ongoing journey: "This storyline, to date, has been probably the hardest storyline I've ever had to broach, really, in terms of continuation of getting the feelings there and keeping them bang on. It's been shattering, but a challenge."
Hinting at what is in store next, she continued: "[There's] high, high drama to come. My goodness, there's so many hills to ride your horse over on this. And I don't know where it's going to end, because I honestly haven't been told and I can't see an end at the moment.
"So I'm just going, 'What next can she possibly have thrown at her?' But it's exciting, exciting stuff to come, I know that."
Sally Webster (Sally Dynevor) was recently tipped to start featuring in the storyline as she puts her own personal safety at risk by growing closer to Frank (Andrew Lancel).
Reports have also suggested that returnee Michelle Connor (Kym Marsh) helps Carla to get her life back on track and stands up to Frank in forthcoming episodes.
Coronation Street continues tonight at 7.30pm and 8.30pm on ITV1.
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Watch a video preview of tonight's Coronation Street double bill below: