Annabel had left her seat and was now jogging along a shop-lined road and looking very excited.

'Right,' she said to the camera, 'I've got to find this station. Oh, there it is!' She pointed to a platform full of waiting people as she jogged up to where a single track railway ended at a set of buffers. She called to the people, 'Excuse me! Is this the tourist railway?'

A few of the people pointed, and Annabel turned around.

'Behind me, right! Thank you!' She jogged over the main road and turned left into the entrance of a large, old-fashioned station ticket hall. 'Gosh, what a lovely old station! Excuse me, hello.' She stopped at the ticket window, where a lady wearing an authentic historical railway uniform was standing. 'How long before the train to Holt leaves?'

'Three minutes,' the woman said, just audibly.

'Three minutes?' said Annabel. 'Oh, gosh! Right, thanks very much,' and she jogged back out onto the main road.

'There he is, Gov,' said Mikey, who was flying along over the A148, 'on the back of that tractor.'

'Keep following him, then,' snarled the Interceptor.

'Yes, Gov'nor.'

'Where are you, Brittany?' asked Annabel, peering anxiously down the road towards the roundabout at the bottom. 'I'm looking out for you near where the station is.'

'Just coming up to this... what is it again?' asked Brittany, turning to face the camera as she jogged along the A149, now lined with fewer trees and more buildings.

'Roundabout,' Glenn's voice said faintly.

'Almost at the roundabout,' said Brittany.

'Almost at the roundabout?' said Annabel. Then, as Brittany rounded the corner into Station Road, 'Oh, yes! I can see you!' She began waving frantically and jumping up and down.

Brittany waved back as she jogged up to Annabel.

'Right,' said Annabel, grabbing her arm and pulling her towards the station, 'here's the tourist railway, and there's a train to Holt leaving in just a minute, okay?'

'Okay,' panted Brittany.

'Come with me,' said Annabel, jogging off energetically, and Brittany staggered after her through the old-fashioned ticket office and onto the platform.

'Wow, look at all this,' said Annabel, as she led Brittany onto a platform full of people climbing into some reddish-brown railway carriages, while the green locomotive attached to them was puffing away on the tracks. 'Hi, everyone!'

Several people turned round and smiled in amusement at the sight of the two women jogging along with headsets and cameramen.

'Right, Brittany,' said Annabel, as they reached the nearest carriage, 'here's your train. You can have a nice, long ride now.'

'Great,' said Brittany, climbing aboard. 'Thanks, Annabel.'

'Right,' said Annabel, 'I'm going back to my chair.'

Mikey, still watching Alvin from the air, said, 'There's not much more to this road, Gov. They'll have to turn off at that T-junction.'

'Get ahead of him, Mikey,' said the Interceptor. 'See what's there.'

'Yes, Gov.'

As Alvin saw the black helicopter swooping overhead, he huddled his back more closely against the edge of the trailer.

'Yes!' crowed the Interceptor, as Mikey flew over some green fields. 'Key position!'

The blue and yellow flag that marked Alvin's key was flying over a body of water, which was not exactly large, but big enough to be seen from the helicopter.

'Take me down, Mikey,' said the Interceptor.

While Brittany's train was trundling along, Alvin's tractor turned left at the T-junction Mikey had noticed, drove on a little further and at last pulled up to a grass verge at the side of the road. On this verge, cars were parked in a haphazard fashion, wherever there was space available between the trees. On the other side of the road was open farmland and a sign saying, among other things (though these were unclear on-camera): Welcome to Holt.

Alvin jumped down from the trailer, called, 'Thanks, man!' to the driver as he was pulling out, and then started jogging past the cars and trees.

'Annabel?' said Alvin, seemingly oblivious to the Interceptor's helicopter flying at low altitude nearby.

'Alvin, hi!' said Annabel, as she jogged up to her seat outside the pub. 'Have you got your key yet?'

'No, not yet,' said Alvin. 'I'm just coming up to this gate which says "Spout Hills" on it. That dude didn't bring me to the wrong place, did he?'

'Um...' Annabel, now back in her seat, frowned down at her map. 'No, that's okay, it's just another name for Holt Natural Springs.'

'Well, that's helpful!' said Alvin, as he walked around the gate and onto the footpath that curved round it to his left. 'Okay, I'm going into this springs place.'

'Right, brilliant,' said Annabel. 'You need to look for a blue and yellow flag.'

'Okay,' said Alvin, jogging along the footpath through the trees.

'That's the road back to where Annabel is,' said Mikey. 'I reckon he'll have to get on there to meet up with his girlfriend.'

'Never mind where Annabel is,' said the Interceptor. 'Look, key position! Take me down, Mikey.'

'Alvin,' said Brittany, peering out of the window of her railway carriage, 'watch out for the Interceptor. I haven't seen him since I left that maze.'

'Chill out, Brittany, I will,' said Alvin, now approaching a flat body of water the size of a large pond or a small lake. 'Annabel, this flag you told me about is on a pontoon right in the middle of this, like, pond or something.'

'In the middle of a pond?' said Annabel.

'Yeah,' said Alvin. 'How am I supposed to get to it?'

'Is there anyone you can ask?' said Annabel.

Alvin looked around. There were quite a few tourists, and two men in green overalls pruning a tree.

'I'll ask these groundskeeper-looking guys,' said Alvin, and he jogged over to them. 'Excuse me.'

'All right, mate?' said one of the groundskeepers, turning round with his shears dangerously open, and looking not at all surprised to see Alvin with his costume, headset and cameraman.

'Yeah, I'm cool,' said Alvin. 'I'm supposed to get a key that's over there somewhere.' He pointed.

'Oh, you've come for the key?' said the other groundskeeper. 'Come with me and I'll show you.'

The black helicopter landed, and once again the Interceptor got out. He ran towards where Alvin was, and hid behind a tree some yards away from him.

'He's got no idea you're there, Gov,' Mikey remarked, as Alvin stood with his back pointing right at where the Interceptor was hiding. The groundskeeper had taken him to the edge of the water and was showing him a piece of string.

'Your key's on the end of this,' the man was saying. 'You just have to pull it up.'

'Okay, thanks,' said Alvin, getting into a crouching position, and he began to pull. 'Oh... it's heavier than you'd think!'

'Are you okay, Alvin?' said Annabel. 'Have you got your key yet?'

'Almost,' said Alvin. 'I'm having to pull it up on this string. Oh, eww!'

'What's the matter?' asked Annabel, laughing.

'There's all kinds of weeds and stuff,' said Alvin, pulling a soggy, dark green mass off the string and dumping it beside him with a noisy splat. 'That's what's weighing it down!'

'Well, keep going,' Annabel said bracingly.

'I am,' said Alvin, making a face as he had to free the string from another tangle of slimy pond matter.

Brittany's railway carriage was pulling up to a small platform in the middle of the woods, where a group of people was waiting to get on.

'Annabel?' said Brittany.

'Yes, Brittany?' said Annabel.

Brittany was looking at the station sign out of the window. 'We've stopped at a place called Kelling Heath.'

'Right,' said Annabel, 'then you're over halfway there. The next station is Holt, where you need to get off.'

'Okay,' said Brittany. 'And then what do I do?'

'I'll just have a look and see what's the quickest way for you to meet up with Alvin,' said Annabel, and did so. 'Right, Brittany, when you come out of Holt Station, turn right and go along Cromer Road. That goes almost directly to where Alvin is, and by the time you get there, he should be coming along in the other direction.'

'That road I had to run all along before was named Cromer Road,' said Brittany, frowning confusedly at Glenn's camera.

'That's all right, don't worry,' said Annabel. 'It's a different Cromer Road.'

'Oh, okay,' said Brittany, her expression clearly showing that she thought this silly.

'Alvin?' said Annabel.

'Still pulling, Annabel,' said Alvin, pre-empting her next question. 'There can't be much more to go now.'

'Right, good,' said Annabel. 'Listen to me, Alvin. When you've got your key, you'll need to get onto Cromer Road, where Brittany's going to be coming from the other direction. It's a bit of a way to where she is, so you'll probably need another lift.'

'Comber Road?' said Alvin.

'Cromer!' Annabel said loudly. 'C-R-O-M-E-R!'

'Okay,' said Alvin. 'Ah! Freakin' finally!'

At last, the key was in his hand. He unhooked it from the string, pulled off a lot of soggy greenstuff, shook as much of the water from it as he could and then held it up with a triumphant cry of, 'Yes! I have my key now, Annabel!'

'Oh, fantastic!' said Annabel.

The Interceptor, pursued by his own cameraman, was bent double in an attempt to be inconspicuous as he swooped along the level, grassy terrain. Alvin was pulled suddenly and harshly out of his reverie by an electronic sound, followed by someone else's triumphant cry of, 'Yes!'

Alvin whipped round to face away from the Interceptor, but it was obviously too late.

'I got you, pal!' said Interceptor.

'Oh crud,' muttered Alvin, backing away from the Interceptor and looking acutely embarrassed.

'Alvin?' said Annabel. 'What's going on? I thought I heard the Interceptor.'

'Yeah, you did,' said Alvin. 'He's right here with me.'

'Well, be sure to keep your back away from him!' said Annabel.

'Uh... yeah,' Alvin said sheepishly. 'Where am I going now, Annabel?'

'Back the way you came,' said Annabel, 'along the A148 a little bit, and then you need to do a couple of left turns to get onto Cromer Road. Look out for a lift when you get there.'

The Interceptor had walked off a little way and was now getting onto his own black motorcycle, which happened to be parked around the corner.

'I'm going to have another go at that girl chipmunk, Mikey,' he said.

'Good idea, Gov,' said Mikey's voice, as the Interceptor pulled on his helmet. 'I don't think you did get her at that maze, y'know.'

'Shut up, Mikey,' snarled the Interceptor, revving up his engine. 'Where's this road they're supposed meet up on?'

'You'll have to take a couple of turns to get to it, Gov,' said Mikey. 'I'll talk you through it.'

Alvin was jogging backwards along the grass verge of the A148, over some ground his tractor had covered earlier, heading in the same direction as the traffic and looking out for a lift among the cars that were zipping past him. Very soon, an open-backed builder's van pulled up alongside him and the driver leaned across the handbrake to the open window.

'Need a lift, mate?' he asked.

'Yes please,' said Alvin. 'I need to get onto Cromer Road.'

'Whereabouts on Cromer Road?' asked the builder.

'Wherever my friend is,' said Alvin. 'She'll be running along the sidewalk in the other direction... I hope.'

'Right-oh,' said the builder. 'Jump on.'

Alvin hopped onto the back, with Andy right behind him, and found himself sitting alongside an adjustable ladder and some bags of cement.

'Holt Station, here it is!' squealed Brittany, jumping up and down with excitement, and then heading for the nearest door on the carriage. 'Oh... where's the door handle?'

'On the outside,' came Glenn's faint answer.

'The outside?' shrieked Brittany.

'You have to open the window and reach out,' said Glenn.

'Oh my God!' said Brittany, but she did it, which wasn't easy because her small stature meant she actually had to jump up and hang out of the window to reach the handle. 'Okay,' she said, jumping back down before the door swung away with her still on it, and then hopping out onto the platform. 'That is not safe!'

'Are you okay, Brittany?' asked Annabel.

'Yeah, I'm cool, Annabel,' said Brittany.

'Where are you?' asked Annabel.

'I just got off the train,' said Brittany, jogging briskly along. 'I'm going down to Cromer Road.'

'Be as quick as you can,' said Annabel. 'You've only got just under two minutes!'

'Oh no!' cried Brittany, quickening her pace.

Alvin's vehicle was driving past rows of buildings with signs on them showing that, though they had clearly once been quaint cottages, they were now business premises. They took a left turn, and then a right, onto a road lined with similar buildings that looked to be residential.

'Annabel?' said Alvin. 'The driver's just turned right.'

'Right?' said Annabel, looking at her map. 'Um... yes, there is a right, after a couple of lefts.'

'We took a couple of lefts earlier,' said Alvin.

'Are you on Cromer Road?' asked Annabel.

'Probably,' said Alvin, with a shrug towards the camera. 'There's fields on my left... the driver's right... and houses on the other side. Brittany, what's it look like where you are?'

'It's just all trees right now, Alvin,' said Brittany.

'Come on!' said Annabel. 'You've got just over a minute!'

Just then, the Interceptor's black motorcycle overtook the builder's van with a roar of its engine, almost causing an accident on the other side of the road.

'Brittany, watch out!' said Alvin. 'The Interceptor's just gotten ahead of us! He's on a motorcycle!'

'Oh no!' shrieked Brittany, looking round in alarm.

'You're going against traffic, right?' said Alvin.

'Yeah,' said Brittany.

'Then you'll see him coming,' said Alvin. 'And I'll be right behind!'

'Forty seconds!' said Annabel.

'I'm coming up to some buildings,' panted Brittany. 'I can see... aaah! The Interceptor!'

'Twenty-five seconds!' said Annabel.

Shrieking with panic, Brittany turned to face the road as the motorcycle approached and the Interceptor held out his arm to fire at her.

'Yes!' he cried, though Brittany had kept her back to him and was now side-hopping along the pavement.

'Brittany!' yelled Alvin. 'I can see you!'

'Ten seconds!' yelled Annabel.

'Brittany, face the traffic!' yelled Alvin.

'I can't!' squealed Brittany, as the Interceptor's motorcycle came back from the other direction, now on the opposite side of the road (from where he couldn't really point his left arm at her anyway). But then he zoomed past Brittany and she whirled round to face forwards; her eyes widened as she saw the van coming towards her and Alvin leaning dangerously over the side, holding out his left hand to her.

'Tag me!' he yelled.

'Three... two...' said Annabel.

Brittany held out her own left hand, and Alvin slapped it with his.

'One!' said Annabel. 'Oh, my gosh – did you make it?'

'Yes!' said Brittany, collapsing onto the ground with exhaustion and relief, while Alvin's van found a suitable place to pull over and he jumped out before it had come to a complete stop.

'We did it, Britt!' he yelled, rushing towards her.

'Yeah,' said Brittany, her face breaking into a smile. 'Oh my goodness! That was... absolute murder.'

'Oh, come on, it was fun!' said Alvin, chuckling as he helped Brittany to her feet.

'Well done!' said Annabel at her table. 'Wait there for me, and I'll come and open the packs with you.'

By the time Annabel found Alvin and Brittany, they were out of the way of the road and pavement, standing around in a grassy area past which Brittany had run earlier, when making her way out of Holt Station.

'Here you are!' said Annabel, rushing up to Alvin and Brittany with her arms outspread, holding a black box in each of her hands. When she reached them, she stooped down to envelop them both in a hug, which Alvin in particular seemed to enjoy.

'Hi, Annabel,' said Brittany.

'Right,' said Annabel, putting down her boxes, 'let's get those packs off and see if he got you.'

'I got them all right, Annabel!' yelled the Interceptor, suddenly zooming onto the grass several yards away from them on his motorcycle, with the visor of his helmet open. 'I got him at his key position, and I got her on the road!'

'Well, let's see, shall we?' said Annabel, still crouching down, as she took Brittany's key from her.

'Uh... here,' said Alvin, no longer elated, but looking rather sheepish as he handed Annabel his pack. Steadying it against the ground, she turned the key in the lock, watched agitatedly by Brittany and resignedly by Alvin. The pack refused to open.

'Oh, you got zapped, you fool!' said Brittany, giving Alvin a light shove on the arm, which he answered with an apologetic shrug.

'Oh no, he got you!' Annabel said jovially. 'Do you think he got you as well, Brittany?'

'No way,' said Brittany, as she handed Annabel her pack.

'Let's hope you've got the money, then,' said Annabel, as she took Alvin's key from him. There was a moment's tension as she grappled with the lock, then she was able to pull back the lid and reveal the array of five pound notes.

'Yes!' Alvin and Brittany both squealed, jumping up and down, then turning to each other for a hug.

'Oh, fantastic!' said Annabel, flinging her arms around both of them. 'That's your donation to the Woodland Trust! Well done!'

The Interceptor, still lurking some distance away, looked disgusted. He turned his back on the scene, leaving his motorcycle where it was, and said, 'Come and pick me up, Mikey.'

'Right,' said Annabel, letting go of the two chipmunks at last, and picking up the black boxes she had brought. 'Thank you very much for playing. You've been great contestants, and I'd like you each to have one of these Interceptor adventure packs. You've got a compass and binoculars there, and a lovely map of North Norfolk.'

'That'll come in useful,' Alvin couldn't help saying, as he accepted his gift from Annabel. 'Thanks, Annabel.'

'Thank you, Annabel,' said Brittany in her turn.

'Well,' said Annabel, turning to the camera, 'I hope you enjoyed that very special celebrity episode of Interceptor as much as I did. Goodbye for now!'

The Interceptor, climbing into the helicopter beside Mikey, said, 'They got lucky, Mikey.'

'Where to now, Gov'nor?' asked Mikey, as the Interceptor strapped himself in.

'Where d'you think?' snapped the Interceptor. 'Back to the lair.'

'Okay, Gov,' said Mikey, taking off for the last time that day.