Terrified and in severe pain deep down in the mine, Katie is forced to crawl her way through a tunnel in a desperate bid to escape as her chances of rescue are looking bleak. Will she ever see husband Declan again?
Here, Sammy Winward - who plays Katie - reveals the full details of what fans can expect from the dramatic storyline.
How frightened is Katie after the fall?
"She's terrified! Just before she falls down the mineshaft, she's had a huge argument with Declan. Even though they've only just got married, he's not sure how he feels about her anymore and vice versa. So Katie is already feeling horrendous about that when she falls down the mineshaft.
"At first, Katie thinks there's a possibility of getting out because Declan throws a rope down and also tries to pull her up with his coat. But Declan's attempts to rescue her don't work and then she actually falls deep down into the mine. After that, Katie realises that she doesn't have much hope of getting out unless she takes action herself."
How bad are Katie's injuries?
"Her injuries are really bad. The first time she falls, she knocks herself out and ends up with head injuries. When she falls for the second time, it's quite a big fall and she shatters her pelvis. That means she can't walk and she basically feels like she's been split in two."
Can she hear the rescuers up above?
"Initially Katie can hear Declan, Andy and Moira who are trying to rescue her - that's when she's on the first ledge. She can't see them, it's just hearing their voices because she's already deep down in the mine. It's when she falls down again that she can't see or hear anybody."
How do things progress from there?
"Initially Katie has a source of light because the quad bike she was riding on at the time of the accident has also fallen down into the mine and its headlights are on. But then the battery goes out and Katie is left in darkness. The only source of light she has after that is her phone. She's hoping desperately that she's going to have a signal, but unfortunately she doesn't."
Katie decides to make her way through a tunnel rather than staying in one place to be rescued. Why is that?
"Well, she's lying on the floor but then debris starts to fall from above, so she knows that she has to move. Because of her injuries, she has to crawl through the tunnel using her arms to pull herself forward. She's in absolutely excruciating pain, and to make matters worse she's crawling over debris and barbed wire. But she knows that she has to do it to get out.
"It's pretty much the tunnel from there on in and she's continuously crawling from that point forward. From then on, what's behind her is blocked anyway so she has to keep going forward."
What are the conditions like?
"She's crawling along in mud and water, and there's blood everywhere. It's horrendous! She gets her leg hurt on the barbed wire, screams out in pain and has to rip her shirt to stop the bleeding herself. She's also freezing cold because of the water.
"Because it's pitch black, Katie has no idea how long she's been down there for. She definitely loses a sense of time."
What was the storyline like to film?
"Most of the scenes were filmed at our studios in Leeds on a purpose-built set. They built three different parts for the scenes I had to do - there was the initial drop where Katie falls, the part where she has to lie with a shattered pelvis, and then the third bit was the tunnel. So it was fantastic, really! It was an amazing design and it's definitely the most dramatic storyline that I've done."
Did you have to get really dirty during filming?
"Oh my God, like you wouldn't believe! I've never felt so grotty in all my life. I had four layers of clothing on, including a wet suit. They were sodden and all covered in wet mud. I also had to have gravel rubbed into my hair, wet mud on the top and then dried blood around my face. I was pretty much covered from head to toe.
"I was filming the scenes for three or four days, and they didn't want me to wash my hair or clean my nails at the end of each day as they wanted to make it look realistic."
Did the poor conditions make it easy to identify with Katie?
"On the last day in the tunnel, absolutely - it was freezing cold. We did have heaters and they gave me hot water bottles, but it was so difficult to get in and out of the clothes that I just had to stay in the wet clothes the whole time. The water being pumped in to the tunnel was freezing."
Back in the village, a candlelit vigil is behind held for Katie at The Woolpack. How would she feel if she knew that?
"I don't know how anyone would feel about that! On one hand it's lovely, but I don't think she'd want people to have given up on her. Megan has returned to the village to support Declan and she's actually the one who says that people shouldn't be giving up on Katie. She's the last person that you'd expect to say that."
Does Katie have time to reflect on the row she had with Declan?
"Yeah, definitely. She drifts in and out of consciousness, and there's certainly parts where she thinks she is going to die. She has a lot of time down there to think about what's important to her and everything that's happened recently.
"I don't think Katie feels that she did anything too wrong, but she does understand that the arguments have led to horrendous consequences and she's definitely regretting that."
Is there any hope for Katie?
"Well, she actually gives up at one point. Her phone battery goes and it's pitch black, so she drifts out of consciousness again. When she wakes up, she sees a patch of morning light so she decides to make her last effort to get out. That gives her some hope, but you'll have to tune in to see how things turn out!"
> 'Emmerdale' Jason Merrells Q&A: 'Declan thinks he's killed Katie'
> Read the latest 'Emmerdale' spoilers and news
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