Exclusive short story by Anthony Horowitz - only in The Mail on Sunday

Part Two:

In the first part of our story last week, Alex Rider saw Sahara Sands, the daughter of a US government official, being kidnapped at a Colorado ski resort by a mysterious criminal - known only as Da Silva - and his two henchmen.

But what can Alex - whose later exploits as a teenage member of MI6 have sold more than 10million novels and been made into the film Stormbreaker - do?

His secret agent uncle, Ian Rider, is nowhere to be found and Alex is yet to become a spy himself. Even so, he must try to rescue Sahara...

I was running to get help. Six months later, I might have tried to do something myself. Three men had grabbed Sahara - and they weren't expecting trouble.

I might have gone after them, taking the next gondola and tracking them down. It might have occurred to me to stop the gondola in mid-air.

But, of course, everything was very different then. I was 13 years old. I was on my own in a Colorado ski resort called Gunpoint. And I wasn't even certain about what I'd just seen.

Could I really be sure that Sahara was being kidnapped? And if so, why? According to my uncle Ian, Da Silva, the kidnappers' leader, had been involved in some sort of bank fraud. Why would he be interested in the daughter of...

But Sahara's father, Cameron Sands, worked for the US government. He travelled with a pair of Secret Service men. That was when I knew I was right. Whatever was happening to his daughter, it must be aimed at him. He was the one I had to tell.

I stabbed my skis and poles into a mound of snow and ran back as fast as I could to the hotel - not easy in ski boots. You were meant to take your boots off downstairs, but I just clomped right in, through the reception area, into the lift and up to the second floor, where all our rooms were.

Because of the layout of the hotel, I got to the suite I shared with Ian before I reached Cameron's room. Acting on impulse, I went into the suite. Ian had said he was going to the police precinct to talk about Da Silva, but there was a chance he would still be there. If I told Ian what had happened, he would know what to do.

But he had already gone. I turned round and was about to leave when I heard someone talking. I recognised the voice. It was Sahara's dad. He was standing outside on the terrace, talking into a phone.

I went over to the French windows and saw him standing with his back to me. He was talking into the cordless phone from his hotel room. I could tell straight away there was something very wrong - his whole body was rigid, like he'd just been electrocuted. I heard him speak.

'Where is she? What have you done with her Da Silva?'

It had to be him at the end of the phone, calling on a mobile. He'd taken the girl and now he was talking to the dad, just like in the movies. What was he demanding? Money? Somehow, I didn't think so.

If you were into the money-with-menaces business, you'd be after the film stars and multi-millionaires staying at the resort.

Gently, I slid the window open so I could hear more. 'OK,' Sands spoke slowly. In the cold air his breath was white smoke, curling around him. 'I'll bring it. And I'll come alone. But I'm warning you...'

Whoever was talking to him had already cut him off. Sands lowered his arm, the phone sitting loose in his hand.

As far as I was concerned, that should have been it. I liked Sahara but I hardly knew her. Her dad had two Secret Service men somewhere in the hotel. Maybe they were still in the room, waiting for him to come back inside. This was none of my business.

But somehow I couldn't leave it there. At the very least, I had to know what was going to happen. I told myself I wasn't going to get involved, that I was being stupid. But I still couldn't hold back.

When Cameron came out of his room five minutes later, I was waiting for him in the corridor. He had changed into his ski suit and - here was the weird thing - he was carrying his laptop computer.

It was sticking out of a black nylon bag. As he went downstairs he pushed it inside and fastened the zip. There was no sign of the Secret Service men - but I'd heard what he said on the phone: he wasn't going to involve them. Wherever he was heading, he was going alone.

I followed him downstairs, out of the hotel and across to the gondola that carried skiers up to the mountains. I picked up my skis and poles on the way. He had his skis too.

The laptop was hanging around his chest in its nylon bag, slightly hidden under one arm. There weren't many people at the gondola now. Ski school had begun and the various classes were already practising their snowploughs on the lower slopes.

I watched Sahara's dad hold his lift pass out to be scanned, waited a few moments, then did the same. I'd pulled up my hood and put on my goggles.

We got into the same gondola and were only a few inches apart. But even if he looked in my direction, I knew he wouldn't recognise me. Anyway, he wasn't taking any notice of the people around him. He looked sick with worry.

Five minutes later we got out at Black Ridge, a wide shelf in the mountains with three other lifts climbing in different directions. Cameron put on his skis and I did the same. I knew he was a strong skier, but I reckoned I could keep up with him.

I didn't need to worry. He skied only as far as the nearest lift - a double chair - and took it up to Gun Hill. There was just one more lift that went up from here. It led to an area called The Needle.

It was as high as you could get, so high that even on a bright day like today the clouds still licked the surface of the snow. Once again I went with him, just a few chairs behind.

Da Silva was waiting for him at The Needle.

After we got off the lift, I stayed behind, tucked in close to the lift building's brickwork, watching as Cameron Sands skied down about 30 metres to a flat area beside the piste known as Breakneck Pass.

The name tells you all you need to know. It was the only way down, a double black diamond run of ice and moguls that started with a stomach-churning, zig-zagging chute, continued along the edge of a precipice and then plunged into a wood, with no obvious way between the trees.

Not many people came up here. My uncle said you'd need nerves of steel to take on Breakneck. Or a death wish.

Waiting with Da Silva were the fat man and the Korean I'd seen helping him kidnap Sahara at earlier. They had a scared-looking Sahara trapped between them. No one could see me.

I was 30 metres higher up, and the clouds and snow flurries chasing along the mountain ridge separated me from them. I wiped the ice off my goggles and watched.

Cameron said something. Sahara started forward but the two men held her back. Now it was Da Silva's turn. He was smiling. I saw him point at the laptop. Sands hesitated but not for very long. He lifted it off his shoulder and handed it over. Da Silva nodded to his companions.

They let Sahara go and she slithered - I wouldn't even call it skiing - across to her dad. He put an arm around her. The business was finished.

Except that it wasn't. I hadn't decided what I was going to do - until I did it. Suddenly I found myself racing down the slope, my legs bent and my shoulders low, my poles tucked under my arms, picking up as much speed as I could. Nobody was looking my way. They didn't realise I was there until it was too late.

I was moving so fast that, to them, I must have been no more than a blur. I snatched the laptop out of Da Silva's hand and kept going, over the lip and down the first stretch of Breakneck Pass.

In the next few seconds I found myself almost falling off the edge of the mountain, poling like crazy to avoid the first moguls and, at the same time, managing to get the bag strap over my head so the computer dangled behind me.

I nearly fell twice. If I'd had time to think what I was doing, I'd probably have lost control and broken both my legs. But instinct had taken over. I was 20 metres down the chute and heading for the next segment before Da Silva even knew what had happened.

He didn't hang around. I heard a shout and somehow I knew, without looking back, that the three men were after me. Da Silva wanted the computer. Sands had given it to him.

So he and his daughter weren't needed any more. I was the target now. All I had to do was get down to the bottom, which couldn't be more than two or three thousand metres from here. It was just a pity there was no one else around. If I could get back into a crowd, I'd be safe.

I heard a crack. A bullet slammed into the snow inches from my left ski. Who had fired? The answer was obvious but even so I found it hard to believe. Was it really possible to ski in these conditions and bring out a gun at the same time? The snow was horrible, wind-packed and hard as metal.

My skis were grinding as they carried me over the surface. I was grateful my uncle had insisted on choosing my equipment for me; I was using Nordica twin tips, wide under the foot and seriously stiff. It had taken me a while to get used to them but the whole point was that they were built for speed.

Right now they seemed to be flying, and as I carved and pivoted around the moguls I almost wanted to laugh. I didn,t think anyone in the world would be able to catch up with me.

But I was wrong. Either Da Silva and his men had spent a long time training for this or they'd been experts to begin with. I came to a gully and risked a glance back. There were less than 15 metres between us and they were gaining fast.

Worse still, they didn't seem to be exerting themselves. They had that slow, fluid quality you get in only the best skiers. They could have been cutting their way down a nursery slope.

I cursed myself for getting involved in the first place. Why had I done it? This had nothing to do with me.

But then I made it to the woodland. At least the trunks and branches would make it harder for anyone to take another shot at me. I was lucky I'd done plenty of tree skiing with Ian.

I knew that I had to keep up speed otherwise I'd lose control. Go too fast, though, and I'd risk impaling myself on a branch. The secret is balance. Or luck. Or something.

I didn't really know where I was going. Everything was just streaks of green and brown and white. I was getting tired. Branches were slashing at my face; my legs were already aching with all the twists and turns and the laptop was half-strangling me, threatening to pull me over backwards.

One of my skis almost snagged on a root. I shifted my body weight and cried out as my left shoulder slammed into a trunk - it felt as if I'd broken a bone. I almost lost control.

One of the men shouted something. I couldn't see them but it sounded as if they were just inches away. That gave me new strength. I shot forward on to a miniature ramp, which propelled me into the air and through a tangle of branches that scratched my face and tore at my goggles.

I was in the clear. The wood disappeared behind me and I fell into a wide, empty area. But I landed badly. My skis slipped and there was a sickening crash as I dived headlong into the snow. My bones shuddered. Then I was sliding helplessly in a blinding white explosion. My skis came free.

I was aware the surface underneath me had changed. It was smoother and more slippery. I stretched out a hand and tried to stop myself, but there was no purchase at all. Where was I? At last I slowed down and stopped.

Breathless and confused, I was sure I must have broken several bones. The laptop was round my throat and the ground seemed to be cracking up where I lay. No, actually it was cracking up.

As I struggled to my feet, I realised what had happened. I had gone spectacularly off-piste. There was a frozen lake on the west side of the mountain called Coldwater. I had landed right next to it and managed to slide in. I was on the surface of the ice. And it was breaking under my weight.

Da Silva and the two men had stopped on the edge of the lake. All three were facing me. Two of them had guns. My goggles had come off in the fall and Da Silva recognised me. 'You!' He spat out the single word. He didn't sound friendly.

There were about ten metres between us. Nobody moved.

'Give me the laptop,' he demanded.

I said nothing. If I gave him the laptop, he would kill me. That much I knew.

'Give me it or I will take it,' he continued.

There was the sound of something cracking. A black line snaked towards my foot. I steadied myself, trying not to breathe. Water, as cold as death, welled up around me. I wondered how much longer the ice would hold. If it broke I would disappear for ever.

'Why don't you come and get it?' I said.

Da Silva nodded and the Korean man stepped forward. I could see he wasn't too happy about it - I guess he'd been chosen because he was the lightest of the three.

But he wasn't light enough. On the third step, the ice broke. One minute he was there, the next he was down, his arms floundering and his face filling with panic as he tried to grip the sides of the hole. His breath came out as great mushrooms of white steam.

He tried to scream but no sound came out. His lungs must already have frozen.

He had taken a gun with him. They had only one other. Da Silva snatched it from the fat man - at least there was no way he was going to trust his weight on the ice - and pointed it at me.

'Give me the laptop,' he said. 'Or I will shoot you where you stand.'

'What will you do then?' I said. I took another step, moving away from the edge of the lake. The ice creaked. I could feel it straining underneath my feet. 'You can't reach me. You're too heavy.'

'The ice will harden in the night. I'll return for it tomorrow.'

'You think the laptop will still be working? A whole day and a night out here?'

'Give it to me!' Da Silva didn't want to argue any more. I could almost see his finger tightening on the trigger. I had absolutely no doubt that he was about to kill me.

'Alex . . . get down. Now!'

My uncle's voice came out of the wood. As Da Silva spun round, I dropped low, hoping the sudden movement wouldn't crack the ice. At the same time there were two shots. Da Silva had fired first. He'd missed. My uncle hadn't.

Da Silva seemed to throw his own gun away. He had been hit in the shoulder. He sank to his knees, gripping the wound. Blood, bright red in the morning sun, seeped through his fingers.

Ian Rider appeared. I had no idea how he'd managed to follow us down from The Needle. I'd never so much as glimpsed him. But that must have been what he'd done.

He skied to the very edge of the lake and spoke to me, his eyes never leaving Da Silva or the other man.

'Are you all right, Alex?' he asked.

'Yes.'

'Come back over here. Give me the laptop and get your skis back on.'

I did as he told me. I'd begun to tremble. I'd like to say it was just the cold but I'm not sure that would be true.

'Who are you?' Da Silva demanded. I'd never heard a voice so full of hate.

'Your skis. Both of you . . .' My uncle raised the gun. The two men took off their skis. He gestured. They knew what to do. Da Silva and the fat man threw their skis into the lake.

Meanwhile, the Korean had managed to pull himself out. He was lying there shivering, blue with cold.

'Enjoy the rest of the day, gentlemen, my uncle said, and he and I set off together.

Da Silva and the others would have to walk down. It would take them hours - and I had no doubt the police would be waiting for them when they arrived.

And that was it really. What you might call my first mission. Sahara and her dad left the resort that day. I thought I'd never see them again but in fact I met Sahara a couple of years later.

She told me that her dad had been working in the office of America's Secretary of State for Defence - and his laptop had contained classified information about the withdrawal of American troops from Iraq. If it had leaked, the result would have been a huge embarrassment for the US government.

Someone must have paid Da Silva to steal the laptop, but he had failed. So he then engineered the kidnap and the attempted ransom. Something like that, anyway.

I never did find out how my uncle had arrived just in time to rescue me. He said it was just luck, that he'd seen Da Silva on the gondola and followed him up the mountain while I was racing back to the hotel.

Maybe that was true. He also said the gun he'd used was the same gun he'd snatched in the fight the night before. That certainly wasn't.

The funny thing was, we hardly talked about it again while we were in Colorado. It was as if there was an unspoken agreement between us. Ask me no questions and I'll tell you no lies.

When I look back on it, I wonder how stupid I could have been not to see what Ian Rider really was. A spy. But then again, I didn't know what I was either - what he'd made me. I remember he pretended to be very angry that I'd put myself in danger.

But at the same time I could see that secretly he was pleased. He'd been training me all my life to follow in his footsteps, and what happened at Gunpoint had shown him I was ready.

And that was just as well. In a few months time, I'd need to be.