This is the first Casualty story I started writing. It has about 8 chapters already so I thought I'd start posting it. I hope you don't hate it.

The taxi driver only just managed to swerve in time. Cal felt the car judder slightly as it stalled, but at least his colleagues wouldn't be performing emergency operations on him because of someone else's imbecility. The other car was going much too fast, windows blaring and one idiot girl standing up with her head through the sunroof, screaming. As they passed, Cal told himself to behave like a professional and not tell the stupid girls what he thought of them, but the taxi driver couldn't help sending a few choice words in their direction.

He heard the car screech around the corner. The taxi driver started up the engine again.

Cal heard a crash.

Several crashes. Louder even than the music had been. He thought he heard screams too, but that might have been his imagination, letting him hear what he expected to hear.

"Stop!" Cal told the taxi driver. "I think there's been an accident."

"Nothing we can do if there is."

"I'm a doctor."

"Okay. It's your money." The taxi driver stopped the car. Cal got out and hurried in the direction of the noise.

He had no trouble in locating the place where the accident had taken place: a whole section of fence was missing where the car had ploughed into it. Down below him, the car turned a final somersault and then was still, resting on its side as the wheels spun uselessly in the air.

Cal felt in his pocket for his phone and spoke a few crisp words into it, explaining the details of the accident and where the victims could be found – all the information he knew the paramedics would need. "I'm going down to see if there's anything I can do to help, but I won't take any risks."

He was lying of course, and he had a feeling the person on the other end of the phone knew it, but she didn't argue. Cal shoved the phone back into his pocket and began to descend the hill. The paramedics, he knew, would reach the site of the crash from a different road, lower down, but Cal knew it would be quicker for him to climb down than to drive round.

It was sleep and slippery: Cal's foot slipped, sending a shower of pebbles down the hill. He grabbed at a stone that he hoped was firmly embedded in the hill. To his relief, it held his weight. But he was not worried for his own safety: more for the unfortunate people in the car below him. Cal didn't think it likely that he would cause an avalanche, but that was an eventuality he hadn't considered.

He'd never been very good with eventualities. Cal tended to act on instinct and think later. It had got him into a lot of trouble over the years.

Having already started the descent, he was reluctant to give up – and only too aware that climbing up would be a lot more difficult. Cal continued his descent, grasping onto any piece of rock, grass or tree that looked reasonably sturdy. Once he misjudged the strength of something and skidded down the hill a few feet but he managed to take hold of a tree root as he fell and stop himself from falling further.

He stayed where he was for a moment or two, waiting for his heart-rate to slow as he assessed the situation. He could see the car, not that far below him, but the only sound he could hear was the music thumping in the car. If the occupants of the car were still screaming, they couldn't be heard.

Cal moved closer and drew in his breath slightly as he realised the girl who had been standing up was still hanging out of the roof of the car. She was still now and her head was hanging at an unnatural angle. Cal knew that might simply mean she was unconscious: heads generally did hang in an unnatural way when there was nothing to support them, but Cal knew it was unlikely the girl had escaped without injury. He couldn't see her face as it was turned away from him, but it wasn't long before he realised that the red streaks in her hair weren't the result of a dodgy dip-dye.

When Cal reached the car he went straight to the girl in the sunroof. Even with his training, he couldn't restrain a gasp as he saw her face. It was a mess of blood and scratches and her nose was bent further to the right than even the most crooked of noses could naturally be. He pressed a finger to her neck and felt a faint fluttering. The girl was in trouble, but she was alive. He gently took her head in his hands, supporting it and, he hoped, preventing further damage.

"Hello? Is there someone there?"

The voice was soft and quivery. Cal bent down, careful not to loosen his hold on the girls' neck, and peered through the sunroof. He saw a pretty girl with brown curly hair and smudged dark eyeliner. She was holding the arm of a recumbent figure seated beside her. Of the driver he could see nothing: the girl he was holding was blocking his view.

Cal spoke calmly. "Hi. My name's Cal. I'm a doctor. I've phoned for an ambulance and it should be here soon, but I'll do whatever I can to make you all more comfortable while we wait. Can you tell me your names?"

"Emma," came the reply. "The girl you're holding is Izzy; the girl I'm sitting on as Georgia and the driver is Andrea. I'm so glad you're here! I can't get to my phone and I didn't know what we were going to do."

Cal heard a slight sob in her voice and made his voice as reassuring as he could. "It's okay. I'm here now and the ambulance is on its way. Are you hurt, Emma?"

"I think they're all really badly hurt," said Emma. "Do you have anything I could use as a bandage? Georgia has thrombocytopenia and her arm is bleeding quite badly in a couple of places. I'm trying to put pressure on it, but I really need something to soak up the blood."

Cal blinked slightly: he didn't usually meet patients who knew the scientific terms. He quickly recovered himself and adjusted his hold on Izzy's head, supporting her as best he could with one hand. "I'll give you my shirt."

"Are you sure? She is bleeding quite a lot. It'll probably be ruined. But that would be such a big help. I tried to take my dress off but I couldn't do it. I couldn't even tear it."

"I don't mind if you ruin it. It's not one of my favourites," admitted Cal as he shrugged out of it. He grimaced. "My brother bought it for me. The guy has no taste. He works at the hospital too so you might get to see what I mean."

"I'm keeping Georgia's arm elevated above her heart," said Emma. "Is that right?"

Cal nodded approvingly and transferred Izzy's neck to his other hand so he could remove his shirt from his other arm. "That's good: that's exactly what you should be doing."

Emma's voice quivered. "I wanted to make a tourniquet, but I don't know how."

"That's okay," said Cal. "You were right not to attempt it if you didn't know how and when to use a tourniquet – and most people wouldn't. Can you lift Georgia's arm so I can see it, please? That's good. No, I don't think we need a tourniquet, but we'll keep an eye on her." He passed the shirt in through the sunroof. "For now, all you need to do is put one piece of shirt over each wound and apply pressure to it with your hands. If the blood soaks through, you put another layer on top." He watched as Emma followed his directions. "That's good. Keep it elevated as you were doing before. You're doing really well, Emma."

Emma gave him a shaky smile and turned to her friends. "Did you hear that? It's going to be okay. There's a doctor here: his name's Cal and he's called for an ambulance and he's going to help us while we wait for it." She turned back to Cal. "I don't know if they can hear me. I think they're all unconscious. But I thought I should keep talking to them. They might be able to hear."

"If they can hear, I'm sure hearing your voice is helping them a lot," said Cal. "Can you tell me what happened?"

A shadow passed over Emma's face. "We're all going out for my birthday, but we got a bit overexcited. Andrea was driving too fast: she always does. And Izzy had been drinking before we started. So she was standing up on her seat with her head through her sunroof. Georgia was trying to calm them down but Izzy was screaming and the music was on really loud and then we hit something. And then we were just falling." She shuddered and her eyes filled with tears.

"It's your birthday?" said Cal, quite dismayed. As if her day wasn't bad enough already.

Emma nodded. "Yes. But it doesn't seem important now."

"Of course not." Cal imagined it was the last thing on her mind. He just hoped the hospital could give her the present she wanted most: three friends in as healthy a condition as anyone could expect. "Do you know if you lost consciousness at all?"

"I don't think so," said Emma. "But it's so hard to be sure. I don't know. People always say things happened so quickly, but it seemed like the car was rolling over and over forever."

"It is often like that," said Cal. "Don't worry: when you all get to the hospital we can probably find out everything we need. We'll look after you all. Okay, I'm just going to take a look at Andrea if I can. I'll have to turn myself round a bit, I think. But if you need anything or you feel worse or you're worried about Georgia, all you have to do is say, okay?"

"Okay," said Emma.

"Good." Cal gave her as reassuring a smile as he could and lifted his head from the sunroof. He held Izzy's head in both hands again as he performed a careful half-turn. Then he lowered his head again and looked into the front passenger seat.

Andrea's head was on the steering wheel but he couldn't see much else. He tapped lightly on the roof of the car above her head and said her name a couple of times but the girl didn't move. He hadn't expected her to: he didn't doubt that Emma had already tried. Cal tried to manoeuvre his head so he could see more, but he couldn't see very much without giving the paramedics another potential whiplash victim. He'd just have to wait until the ambulance arrived.

He heard Emma talking to Georgia. "There, lovely. That should help a bit. I'm sure the ambulance will be here soon. I hope I'm not squashing you. I can't really move because I'm trying to stop the bleeding, and they have rules about not letting car accident victims move till they'd been checked out. But I'm sure the ambulance will be here soon. Just keep hanging on, okay? All of you keep hanging on." Her voice was bright, but when she spoke again, it faltered slightly. "Please keep hanging on. Please."