Mum's big staring eyes open slowly. 'What happened?' she whispers.

The receptionist has run for the doctor, the families have quietened, apart from one small child who's crying.

'I think you just fainted, Mum,' I say.

The doctor is a thin Asian man with a gentle face. He's kneeling beside Mum, taking her pulse.

'Can you examine my mum today and tell us what's wrong?' I beg.

'Of course I can. Right this minute. We'll just see if you can stand up now,' he says to Mum, carefully helping her.

He leads her off into his consulting room. I try to follow but the receptionist catches hold of me.

'No, you wait there. The doctor needs to see your mother in private.'

So I have to sit down and wait, with everyone else glaring at me because Mum's inadvertently pushed in front of all of them. I pick up a tattered magazine worn furry from thumbing, but I can't concentrate. I stare at the clock and try to imagine what's going on with Mum. She's been in with the doctor for five minutes then ten. What's he doing to her?

Someone's muttering angrily that they have to get to work for their lunch-time shift and now they're going to be late. The little kid is still crying, a dismal wail that goes on and on. Its mother doesn't try to pick it up or even wipe its nose. Someone else stands up and stomps out, giving up on their appointment. Mum's been in there fifteen minutes twenty.

I stand up and start along the corridor.

'Where are you going?' the receptionist calls.

'I'm going to find my mum. She's been gone so long. She might have fainted again. She needs me,' I say.

But just then the consulting-room door opens, and there's Mum, chalk-white and trembling.

'Oh, Mum!'

'I'm OK,' she mutters quickly. She turns back. 'Thank you so much, Doctor. I'll go to the hospital on Monday then, first thing.'

'The hospital!' I gasp.

The room starts spinning, and I wonder if I'm going to faint too.

'It's all right, Destiny. It's for blood tests. But it's not what you think. Come on, darling, let's get out of here, and then I'll tell you,' says Mum, pulling me.

We stand outside the little concrete clinic and Mum holds me by both hands.

'I'm truly OK, darling. I don't know why I fainted like that. I suppose I got horribly worked up inside. I must have made such a fool of myself. Did my skirt ride up when I fell?'

'No, you did it all very gracefully, but I thought for one minute you were dead. Mum, why have you got to have blood tests at the hospital? Are they testing you for cancer?'

'No. That's what I've thought I had, all these months. I was losing so much weight and feeling so weird all the time. But it's nothing like that. The doctor thinks there's something wrong with my thyroid gland,' says Mum.

'What's that? Is it serious?'

'Well, I was crazy to leave it so long, just because I was so scared. The doctor thinks this over-active thyroid is why I've got so thin, and why I feel so worked up and anxious all the time. It even affects your eyes, makes them go all funny, just like mine. But they can cure it, Destiny. When they've tested how much thyroid hormone is in my blood they can give me special medicine and it will sort itself out. He's promised they can make me completely better. Oh, I can't believe it. I've been so worried, but it's all right. We're all right, you and me, babe. We're going to be fine.'

12.

SUNSET.

We stagger through the rest of Sweetie's party somehow. Half the little girls keep peering anxiously at Mum, wondering if she's suddenly going to shout at them too. Mum herself stays bright red. Even her chest is painfully mottled. She smiles whenever the camera points her way, she sings Happy Birthday to Sweetie when the cake's brought in, and she even chats to the mums and nannies while Mr Humbug organizes party games but her fists are clenched. She doesn't chat to Dad. She doesn't even look in his direction.

Dad is trying to seem ultra-cool and relaxed, lolling around and laughing with Sweetie or mock-wrestling with Ace but he's not looking at Mum. He keeps getting texts on his phone and going off into a corner to look at them.

Rose-May talks earnestly to the Hi! journalist, maybe begging her not to write about the banished birthday guest. Sweetie carries on with her party valiantly but her laughter is high-pitched, and when she fails to win a party game she bursts into tears.

'Oh, Sweetie, you mustn't cry on your birthday! It's only a silly game!' Mum says, though she promised Sweetie she'd win every single game. 'Now come along, you don't want to have red eyes and a blotchy face in the photos, do you?'

Sweetie stops crying almost immediately, and even gives the little girl who won a big kiss, but she spends the rest of her party with her thumb in her mouth. People start to leave, though the birthday food is mostly untouched and Mr Humbug is only halfway through his party repertoire.

We carry on grimly until the last guest is gone. Mr Humbug and Miss Barley Sugar and Miss Lemon Drop get paid and go. The Hi! Magazine people pack up all their equipment and go too. The party planners roll up the white drapes and the rugs and gather the jars of sweets and the fairy lights. Rose-May leaves, shaking her head. The party's over.

Then it starts.

Mum walks up to Dad and slaps him hard on the face. Claudia takes hold of Sweetie and Ace and hustles them out of the room. She hasn't got a spare hand for me. She calls me but I ignore her, standing at the door.

'Don't you dare slap me around, Suzy! Do that again and I'll slap you straight back, right in the chops.'

'How dare you invite that little tart to Sweetie's party!'

'Liz is a friend. I've got a perfect right to invite who the hell I want to my kid's party.'

'Who was that child? Is she yours too?'

'What? Are you crazy? Liz is only a kid herself. She brought her little niece poor little moppet, she's probably traumatized, you yelling at her like that. I've had just about enough of your jealous tantrums, Suzy.'

'And I've had enough of your lies and your girlfriends. I'm sick of all this sneaking around, all these whispers and texts and secret meetings. If you want her so much, why don't you clear out and go off with her?'

'All right I'll do just that,' says Dad.

He stands up and walks to the door. I try to catch hold of him, crying, but he brushes me to one side, barely looking at me. He walks right out of the house.

Mum sits on the sofa, thumping the cushions with her fists, tears spilling down her red cheeks.

'Oh, Mum,' I say, but when I try to put my arms round her she wrenches away from me. 'Don't cry, Mum. He'll come back,' I say, over and over.

I'm sure he'll come back. Maybe he'll stay out overnight again, but he'll be back in the morning.

But he doesn't come back, not for the whole of Sunday. He's not back on Monday. Claudia says we still have to go to school. Mum doesn't say anything at all. She just stays in bed most of the time, crying.

I don't tell anyone at school. I wear my black T-shirt and jeans and mittens day after day. I wash them out at night and hang them over the towel rail in my bathroom. I don't concentrate in class. I compose new songs instead. I am especially pleased with In My Black Clothes.

I am in my black clothes,

I wear the colour of death.

I sob, I sigh, I wonder why

I go on drawing breath.

Nobody loves me, nobody cares,

I wander the world alone.

I cannot eat, I cannot drink,

Cannot talk on the phone.

I hold my tongue and close my eyes,

I shut my mouth up tight.

I am in my black clothes

Won't someone see my plight?

I write it down in my school jotter and then tear it out, ready to stick in my blue velvet notebook tonight. But the song flutters out as I trudge to the classroom door when the lunch-time bell goes, and my teacher, Lucy, picks it up. Oh no, oh no, oh no.

She glances at it and then stares at me. She's looking anxious. 'What's this, Sunset?'

'Nothing, Lucy,' I say stupidly.

'Did you write this? It's very disturbing.'

I see Sheba nudge Lila.

'Wonky Gob's written a dirty poem!' she says delightedly.

'Read it out, Lucy!' Sheba begs.

'Go on, give us a treat,' says Lilac.

Lucy holds my page up. Oh God, please don't let her read it aloud. They will all laugh at me and I will die.