By 3 p.m., I’m standing in a crowd of runners, formulating a plan for my new career. All I need to do is meet Sage Seymour, start chatting about clothes, offer to style her for an appearance … and I’ll have an in. It’s all about who you know, and Sage Seymour is the perfect person to know. And this is the perfect event to meet her! I mean, I’m actually in her team! I have every reason to talk to her, and I can easily edge the conversation on to red-carpet trends while we’re sprinting along together. I haven’t seen her yet, but my eyes are swivelling around, and I’m poised for action as soon as I spot her.

A bell sounds, and all the runners start pressing more closely together. The cocktails I drank with Danny are starting to creep up on me, and I slightly regret that last Malibu Sunrise now … but never mind. The endorphins will soon kick in.

It’s quite a spectacle, this Ten Miler race. It starts at Dodger Stadium and it goes along Sunset and then on to Hollywood Boulevard. According to the welcome pack, the route ‘passes many Hollywood landmarks’, which is brilliant, because I’ll be able to sightsee as I run! I’ve already checked in, and I can’t believe how many people are doing it. Everywhere I look, I see runners limbering up and jogging and adjusting their shoe laces. Music is playing through loudspeakers and the sun is shining hazily through the clouds and there’s a smell of sunscreen. And I’m part of it! I’m standing in the middle of Group One, about ten feet away from a massive great metal arch which is the start of the race, with a number taped to my chest (184) and a special chip in my shoe. Best of all, I’m wearing the fab team baseball cap which was waiting for me at the hotel desk. It’s bright turquoise, with TEAM SAGE in white letters. I feel like I’m in the Olympics!

Yet again I scan the crowd, searching for another TEAM SAGE turquoise baseball cap, but the runners are too closely packed together to see much. She has to be here somewhere. I’ll just have to find her when we start running.

As I’m doing a leg stretch I catch the eye of a wiry black girl limbering up beside me. She looks at my baseball cap and her eyes widen.

‘You’re in the Sage Seymour team?’

‘Yes.’ I try to sound casual. ‘That’s right. I’m with Sage. We’ll be running together, and chatting, and … everything!’

‘Wow. You must be good. So, what time are you hoping to make today?’

‘Well.’ I clear my throat. ‘I expect I’ll take about … um …’

I have no idea. Ten miles. How fast can I run ten miles? I’m not even sure how fast I can run one mile.

‘I’m just hoping to improve my personal best,’ I say at last.

‘I hear you.’ The girl stretches her arms over her head. ‘What’s your race strategy?’

Meet Sage Seymour, talk about clothes and wangle an invitation to her house, flashes through my mind.

‘Just … run,’ I say with a shrug. ‘To the end. You know. As fast as I can.’

She stares at me blankly, then laughs. ‘You’re funny.’

The runners are clustering together even more tightly. There must be at least a thousand people, stretching back as far as the eye can see. And despite my jet lag, I feel a sudden burst of exhilaration as I bounce lightly in my new hi-tech shoes. Here I am! Running in a high-profile race in LA! It just shows what you can do if you put your mind to it. I’m about to take a photo of myself and send it to Suze when my phone rings and it’s Mum. She always calls last thing at night, just to tell me that Minnie’s got off to sleep OK.

‘Hi!’ I answer the phone in delight. ‘Guess what I’m doing.’

‘You’re on a red carpet!’ exclaims Mum excitedly.

Every time Mum phones, she asks if I’m on a red carpet. The truth is, not only have I not been on one, I haven’t even seen one. Even worse: Luke had an invitation to a premiere last time we were here, and not only did he not go, he didn’t even tell me about it until it was too late. A premiere!

This is why I can’t rely on Luke to get me into anything cool. He has completely the opposite view of LA from me. All he’s interested in is attending meetings and being on permanent BlackBerry call – i.e., business as usual. He says the work ethic in LA is something he really relates to. The work ethic. Who comes to LA for the work ethic?

‘No, I’m running in a charity race. With Sage!’

Mum gasps. ‘You’re with Sage Seymour? Oh, Becky!’

‘I’m not exactly with her right this second,’ I admit. ‘But I’m going to catch up with her while we’re running. I’ve got a TEAM SAGE baseball cap,’ I add proudly.

‘Oh, love!’

‘I know! I’ll take a picture of it. Show Minnie. Is she OK? Fast asleep?’

‘She’s fine, fine!’ says Mum breezily. ‘All snuggled up in bed. So, who else have you met? Anyone famous?’

Lois Kellerton flashes through my mind.

No. Don’t even think about it. I love my mum, but if you tell her anything, it’s all over Oxshott in a nano-second.

‘There are loads of celebs in the race,’ I say vaguely. ‘I think I just saw a guy from Desperate Housewives.’ It could have been him, or it could have been a different guy, but Mum won’t know.

A klaxon is sounding. Oh God. Is that the race starting?

‘Mum, I have to go,’ I say hastily. ‘I’ll call later. Bye!’

That was the start of the race. We’re off. We’re running. I’m running too! Feet and arms are blurring around me as the runners jostle for position and I breathlessly try to stay with them.

God, they’re fast.

I mean, it’s fine. I’m fast too. I’m totally keeping up with the others. My chest is already burning, but that’s OK, because the endorphins will kick in, any minute.

The most important thing is: where’s Sage?

As the crowd thins out, I’m able to get a better view of my fellow runners. I’m scanning the heads desperately for a turquoise baseball cap … She must be somewhere … I can’t have missed her, surely …

There! I feel a burst of joyous adrenalin. She’s right up at the front, of course. OK, time to make my move. I’ll sprint up to her casually, gesture at my hat and say, ‘I think we’re on the same team.’ And our close friendship will begin.

I’ve never really considered myself an athlete before, but as I charge forward, it’s like some invisible force is powering me. I’m overtaking the wiry black girl! I’m on fire! I’m exhilarated! But still the turquoise cap is bobbing along ahead of me, tantalizingly out of reach, so I put on an extra spurt of energy. Somehow I succeed in drawing level with her. My face is boiling and my heart is hammering in my chest, but I manage to point at my hat and gasp, ‘I think we’re on the same team.’

The turquoise baseball cap turns … and it’s not Sage Seymour. It’s some girl with a pointy nose and brown hair who just gives me a blank look and ups her pace. She’s not even wearing a TEAM SAGE cap, either, just a plain turquoise one. I’m so disconcerted I stop dead, and nearly get knocked over by a horde of runners.

‘Jesus!’

‘Out of the way!’

‘One-eight-four, what are you doing?’

Hastily I move to one side and try to catch my breath. OK, so that wasn’t Sage. But never mind. She’ll be here somewhere. I just have to keep my eyes open for turquoise … turquoise … Yes! Over there!

With a fresh surge of adrenalin I plunge into the race again and chase after another turquoise baseball cap. But as I draw near, I can see already that it’s not Sage. It’s not even a girl. It’s a skinny, Italian-looking guy.

Bloody hell. Panting hard, I head to a water station and take a sip of water, still desperately scanning the crowd of runners, refusing to give up. So I’ve had two near-misses. Never mind. I’ll find her. I will. Wait, there’s a flash of turquoise up ahead. That must be her …

An hour later, I feel like I’ve moved into a parallel universe. Is this ‘The Zone’? It feels more like hell. My lungs are pumping like pistons; my face is sweaty; I have blisters on both feet; I want to die … and yet still I’m moving. It’s as if some magic force is keeping me going. I keep seeing turquoise baseball caps in the crowd. I keep chasing them. I’ve approached one blonde girl four times now. But none of them is Sage. Where is she? Where is she?

And where are these bloody endorphins? I’ve been running for ages and haven’t had a single one. It’s all lies. Nor have I seen a single Hollywood landmark. Have we even passed any?

Oh God, I have to drink some water. I head to the next water stand, decorated with helium balloons. I grab one paper cup and pour the water over my head, then gulp at a second. There’s a crowd of cheerleaders in red costumes doing a routine nearby, and I look at them enviously. Where do they get all that energy from? Maybe they have special springy cheerleaders’ boots. Maybe if I had glittery pom-poms to shake, I’d run faster.

‘Becky! Over here! Are you all right?’ I straighten up, panting, and look around in a daze. Then I spot Luke on the other side of the barricade. He’s holding a Ten Miler flag and gazing at me in alarm. ‘Are you all right?’ he repeats.

‘Fine.’ My voice comes out rasping. ‘All good.’

‘I thought I’d come along to support you.’ He eyes me in amazement as I stagger towards him. ‘You’re making incredibly good time. I didn’t realize you were so fit!’

‘Oh.’ I wipe my sweaty face. ‘Right.’ I hadn’t even thought about how quickly I was going. The whole race has been a blur of chasing turquoise baseball caps.

‘Did you get my text?’

‘Huh?’

‘About Sage pulling out.’

I stare up at him blankly, the blood still pumping in my ears. Did he just say …

‘She sends her apologies,’ he adds.

‘You mean … she’s not in the race?’ I manage. ‘At all?’