'Initially I thought of a ring, or a brooch or a pendant but my tanzanite wouldn't really suit a ring. The setting would compromise the beauty of the cut. It must be seen in the round. And I decided against a pendant because what I want is for the wearer to be able to really see the piece whilst it's on. No point having almost 40 carats of eye-clean vBE tanzanite around your neck if you can't b.l.o.o.d.y see it. And brooches are too static. So that's why I thought something for the wrist. Near a pulse point. And I want it to move I don't want a front and back. I want it to be kinetic. Somehow.'

Kitty took the work off Petra again, contemplated it. 'Think: hinges,' she said at length. She looked at Petra, flushed with her idea. 'Hinge all around the stone then the wearer can twist it and turn it and the jewel will always be in the round.'

Petra and Kitty twisted and turned the piece, the boiled sweet knocking this way and that. 'Tanzanite isn't as hard as diamond or sapphire,' Petra said. 'I have to secure it but I want to do so with no visible means of support. And I need to protect the surfaces.'

'You've got your work cut out for you,' Kitty warned her, 'but it'll be your magnum opus. The idea is incredible and I can already see the finished work. Go and talk to Charlton remember his early work, when he first hit the scene? That was based on hinges and intricate engineering.' She paused. 'Christ, Petra this really could be your thing. Once you've resolved the mechanics, you could do similar pieces with other gems. I love it.' She stopped. 'You could charge the earth. You'll have to the materials in themselves will cost a fortune.'

'I know,' Petra groaned.

'But it will be self-perpetuating. Make one or two and they'll be snapped up and then you'll be commissioned in advance. f.u.c.k it you could even sell them on the strength of designs just like this, in wire and boiled sweets.' She peered into the box. There were two more boiled sweets, still in cellophane twists. One green. One red. 'There you go emerald and ruby. Where is your tanzanite?'

'At home,' Petra told her, taking the sweets off Kitty and holding them up to the light.

'Under your mattress?'

Petra nodded.

'Have you considered what it will be like for you when this piece is finished? When it's on someone's wrist and there's no more tanzanite in your bed? How will you feel?' Kitty looked suddenly alarmed. 'Christ, Petra the princess couldn't sleep with a pea under her mattress but how are you going to sleep without your tanzanite there?'

'Oh, the girl will be fine, Kitty,' said Eric, eavesdropping shamelessly, 'because she'll be sleeping soundly in the arms of Prince b.l.o.o.d.y Charming.' He paused for dramatic effect. 'Or, rather, Mr b.l.o.o.d.y Chips.'

Petra reddened. With a jolt, she was back from gold abbeys and tanzanite and platinum cloisters and her potential fame and fortune.

'Go to Ronnie Scott's,' Kitty told her sagely, 'or the Forum wherever he asks you, you must go.' She tossed her head and took a long, lupine sniff at the air. 'This is your time, Petra, this is your time.' She closed her eyes. 'It's given.'

'Was that your girlfriend, then, Mr Savidge?'

'I hope so.'

'You hope so? Lovers' tiff, was it, Mr S?'

'Not really. More like a cataclysmic impa.s.se.'

'Is that why we're here in London, then?'

'Well OK sort of. Are you complaining, guys?'

'No, Mr S!'

'G.o.d, no.'

'Not at all.'

'No way!'

Arlo was currently guiding his flock through Soho. Dragging them, really. The plethora of s.e.x shops and adult-video stores decelerating the Lower Sixth's pace to a l.u.s.ty shuffle.

'Mr S this is much better than school.'

'And if you want to have some you know quality time with your lady, well, me and the guys will be fine, Mr Savidge.'

'In your dreams, Callum Jones. In your mucky dreams.' Arlo laughed. He marched them along Wardour Street and herded them into Frith Street. 'Right, here we are. Ronnie Scott's.'

'Can we smoke, Mr S?'

'No, you b.l.o.o.d.y well cannot.'

Two hours later, after a lot of jazz, zero cigarettes and a quick shower and change of clothing back at the B&B, Arlo was seating his cla.s.s at Pizza Express in Kentish Town.

'Can I borrow someone's mobile phone?' he asked from behind the menu. Felix offered his teacher his. 'Thanks,' said Mr Savidge. 'Mine's an American Hot, with extra mushrooms. I won't be a mo'.'

He loitered on the corner of Prince of Wales Road. Petra's number was now on the screen of Felix's phone. All Arlo had to do was press Call. He clocked the time. If she did want to come along, he was only giving her an hour and a half, and counting. He pressed the b.u.t.ton and cleared his throat of the persistent b.u.t.terfly.

'Hullo?'

'It's Arlo.'

'Oh my! You have a mobile phone?'

'No it's one of my pupil's.'

'I see.'

'Yes.'

No time for pauses. 'Petra would you like to come along tonight? It should be good. Quite raw. The bloke used to be in 3 Colours Red the band, not the film. Do you remember "Sixty Mile Smile"? No? "This is My Time", perhaps? Well will you come anyway? Say you will.'

'Yes, Arlo, I'll come.' But then Petra would have said yes even if it had been Keith Harris and Orville. This is my time, she told herself. This is my time.

It was daft really. She arrived late and yet when they trooped in, they were practically the only people there the main act not due on for a further hour and the support act having no obvious supporters. Petra had been late because she'd turned the contents of her wardrobe over in search of something suitably rock-and-roll to wear. She tried the grunge look but reckoned she looked like a mad old bag lady. She changed into jeans and a T-shirt but worried that she looked as though she'd made no effort. She dared to squeeze into her one mini-skirt but decried her legs as too pasty tried black tights but they looked ridiculous for this time of year. She woke up Lucy, who said sleepily that a vintage ball-gown's always a winner. But Petra had nothing remotely close and nothing she could readily adapt. She phoned Kitty who considered the venue, the band and then said leather and hair loose. But though Petra could oblige with the hair, she owned no leather.

'Perhaps I shouldn't go,' she said.

'Don't be so stupid,' Kitty said. 'It's a b.l.o.o.d.y gig it'll be dark and noisy and you'll be covered in c.r.a.p beer by the end of it anyway. And Arlo probably won't give a d.a.m.n what you wear he just wants you to be there.'

Petra opted for a shortish skirt in a retro print, a white T-shirt, black trainers and a denim jacket because it meant she had pockets for phone, money and keys and didn't have to be enc.u.mbered by a bag. She tied her hair back because the last thing she wanted was for sweat to transform her ringlets to resembling snakes on acid, however rock-and-roll that look might be.

It was still a funny sight to see Arlo chaperoning four hulking Sixth Formers and yet they seemed reluctant to leave his side, even when they went inside. They were also polite to the point of shyness with Petra and though she could hardly hear herself think, let alone speak, she persisted in yelling interesting questions at them above the din, about schools and hobbies and other things that made her sound like their mums' friends. It amused Arlo. Petra sensed it amused him and she was desperate to nudge him, to poke her tongue out, to swear at him, hug him. But she daren't. It felt less of a date and more that she was gatecrashing one of his cla.s.ses. However, they did manage to exchange glances every now and then, which said, G.o.d almighty, this is a gig! We should be necking in some sticky sweaty corner! We should be getting p.i.s.sed on vodka tonics in plastic beakers! We should be jumping around in the mosh like loonies!

The main act was superb, if thunderously loud, and his devoted followers leapt and pogoed and punched at the air. Petra had drunk two vodkas in plastic beakers, fast, and it made her believe she had springs in her legs and could pogo with the best of them. So she gamely did. Arlo delighted in the sight, even more so because his boys were gobsmacked.

'Come on!' they could see her mouth move at them. 'Come on!' She bounced over to take Alex and Thomas by the hand and haul them into the throng with her. Then she did the same to Felix and Callum. And then, once they were leaping about, she made her way over to Arlo.

'No way!' he gesticulated. 'No f.u.c.king way.'

'Yes way!' she shrieked. 'Come on!'

But when she then danced away from him, grinning a sixty-mile, one-hundred-watt smile, he shrugged and bounded into the crowd with her.

It was exhausting, exhilarating. It was deafening and pretty dangerous the floor wet with a slippery c.o.c.ktail of beer and spirits, the amps cranked to maximum output, the lighting trippy, the crowd boisterous. Petra felt hoa.r.s.e and sweaty and a bit drunk and very hot and her feet had been stamped upon and she'd been shoved and jolted and someone's cigarette had come perilously close to her cheek. But she was dancing with Arlo and she felt energized, high and happy.

'I'm so glad I came.'

'What?' He couldn't hear her.

'I'm so glad you came.'

'Sorry?' He could see that she was saying something or other.

She gave up and grinned, snuck a kiss to his lips, and Arlo fondled her bottom and they both knew that his students had very probably seen.

Gig over. Out into the night. Ears ringing, sweat chilling. Makeup a bit smudged. White T-shirt stained. Beer sticky on the legs. The soles of their shoes clogged and tacky with G.o.d knows what. The boys begging Arlo to let them queue for a kebab.

'We didn't smoke, sir.'

'I think there's probably more harm in a dodgy kebab than in a ciggie, Thomas.'

'Can I have a f.a.g instead of a kebab then, Mr S?'

'No, you b.l.o.o.d.y well can't!'

'If we queue for a kebab, it gives you and Miss Petra some, you know, time?'

Arlo and Petra glanced at each other, then they looked at Felix as if he was a genius. So the boys queued and Arlo and Petra stood, out of earshot but in view.

'So,' he said.

'So!' she said.

'Did you enjoy that?'

'Did I! That Chris McCormack is a rock G.o.d!'

'Are you drunk, Flint?'

'I think I am rather! Do I look like the wild woman of Borneo?'

'You look lovely. Tomorrow.'

'Do I look lovely tonight?'

'No. I mean yes. I mean you look lovely. And what I mean is tomorrow. Can I see you?'

'Aren't you tied to your flock?'

'I can leave them in the capable hands of a shepherd at Columbia Records.'

'Your friend?'

'My friend Mike Smith.'

'Good old Mike Smith.'

'He's a lovely bloke you'd like his wife too. I'll introduce you one day.'

'Talking of wives, did you hear about Jenn and your Nige?'

'Of course.'

'I miss Jenn.'

'Come back.'

'I don't know, Arlo. I-'

'Look, I need you to meet me tomorrow, Watford Junction. I'll escort the boys to Columbia Records first thing then make my way over.'

'Watford? Why Watford?'

'I have an errand. I need you there. There's something I have to do. Something I have to tell you. Somewhere I have to go. Something you need to know.'

Chapter Forty-six.

There was a shoe in the fridge when Petra went there for the milk for her morning coffee. But she removed the shoe as if it was nothing unusual, nothing more sinister than a yoghurt past its sell-by date. Something that shouldn't be there but no big deal. Very privately, she was frustrated at the indisputable evidence of her somnambulism because actually, she had awoken feeling well rested and eager to have the day under way. Oh, most auspicious day! A trip to Watford. A mystery! Why Watford? Why, why? She went back into her bedroom and sat on the edge of her bed contemplating the mug of coffee, blowing on it measuredly like a flautist, sending glinting concentric circles rippling across the surface, sipping demurely as if the Nescafe was Noilly Prat.

'Why Watford?' she wondered out loud. But she didn't dare answer herself out loud too. Nothing must tempt fate. She let two thoughts scuttle across her mind: Watford is where my father lives.

Is Arlo all set to do the honourable thing?