His final night in London, a mere thirty hours ago, should have been the ripe time when he was reconciled in joy with his tiny family. Few men could have resisted it, and Vasco da Gama himself could not have been unhappy with such a send-off. And at the beginning Beard was happy. Melissa put on an exceptional show. Even Catriona understood that he was going to America to switch something on, and when he did, the world would be saved. She and her mother, dressed in party frocks, prepared a special early-evening meal, the centrepiece of which was a ball moulded by Catriona's own hands, covered in blue icing with green patches. This was the earth, and on top was a candle, which he blew out in one go, to the little girl's rapture. Melissa and Catriona sang a song about ducklings, Beard sang the first few verses of 'Ten Green Bottles', the only song he knew all the words to. His daughter's arms were round his neck for most of the celebrations. Wasn't this bliss? Almost. He had forgotten to turn his palmtop off, and Darlene rang as Melissa was cutting the cake. Automatically, he took the call and said a little too tersely over her opening remark, 'I'll call you back.' He knew that Melissa had heard a woman's voice and the tension in his own, but nothing in her manner changed, there was no clever presentation of suppressed anger that Catriona would not see and he would. She met his eye, she smiled at him warmly, she poured his wine, she celebrated him.

When Catriona was down for the night and they were alone, he poured himself an extra large scotch and braced himself for a scene. It must come, they should confront it. But she kicked her shoes off and sat close to him and kissed him and told him she would miss him. They talked of other things, of travel arrangements, of his return, and all the while his irritation increased. She was playing with him, she was letting him stew in his guilt. But why should he feel guilt? Someone please tell him why. He was not bound to her exclusively, their arrangement was clear. And she was wrong, he decided, to mask her jealousy with kindness and seduction. She poured him another scotch, she moved closer, nuzzled him, put her tongue in his ear, laid her hand between his legs, caressed him, kissed him again. It was an intolerable deceit. She could feel that he was not aroused. How could she pretend she had not heard Darlene's voice, when she knew that he knew that she had?

And then, while she was telling him an unamusing story about something Catriona had said or done, it came to him, an idea as brilliant and plain as any insight he had ever had. She was not jealous at all, she was untouched, she was indifferent. And for that there could be only one explanation.

He pulled away from her and said as levelly as he could, 'Are you seeing someone?'

It was a move born of his silent anger. But another part of himself, the part that had not touched a drink, did not suspect her at all. His question was more of a punishment, and he reasonably expected her instant denial.

In fact, she was affronted. Her lips formed into the pout he found so likeable, before she said in surprise, 'Aren't you? Michael, of course I am.'

Oh yes, that. The tired old argument from equivalence. The level playing field. Rationality gone nuts, feminism's last stupid gasp.

After a pause while he ordered his thoughts, he said, 'What is his name?'

She looked away and said, 'Terry.'

'Terry?' He spoke in disbelief. All that was foolish in her was contained in this idiotic name. 'And what does Terry do?'

She sighed. It had to come out. 'He's a conductor.'

'On the buses?'

'Orchestras, symphonies. You know, classical stuff.'

But she hated classical music as much as he did, no rhythm, she always said, not hot-blooded enough, not Tobagan and Venezuelan enough for her. She was sitting at the far end of the sofa, looking as if she wished she had lied.

He said, 'And has Terry met Catriona?'

This made her angry. In a tone of mocking sweetness she said, 'That's enough about me. Let's talk about you. That was her on the phone, I suppose. What's her name, and what does she do?'

He waved the question away. He was not prepared to set his waitress against her symphonic conductor. 'Look, Melissa, there's something you're not getting. You're the mother of our child…'

'Oh for God's sake, Michael. And you're the father of our et cetera. I can't believe the crap you talk sometimes. And look…'

She seemed on the point of telling him something else, but just then, Catriona wailed from the bedroom and Melissa hurried away to her. When she came back he was standing on the far side of the room, near his luggage.

'That's right,' she said. 'Go. Fuck off. I'm throwing you out.'

'No need,' he said, and picked up his bag and left.

She phoned him in the morning when he was at Heathrow to tell him she loved him. He told her that he was sorry the evening had ended the way it had and blamed himself. They spoke again when he arrived in Dallas and made up a little more. When he thought about it now he was in two minds. He was angry and jealous and wanted to claim Melissa for himself and stuff Terry's baton down his throat. On the other hand, this Terry was his permission, his passport to more fun with good old Darlene. How much fun of this kind did he have ahead of him? And perhaps this was the point – he had the perfect situation after all. But then he thought of this man in Melissa's bed, or reading Beatrix Potter to his daughter, and he realised that he must give up Darlene and get back to London as soon as he could. But then, what about Darlene? Hopeless, to think about it now when he was so weary, when being in Lordsburg tomorrow would clarify everything.

He fell asleep fully dressed on the bed, with the palmtop still in his hand.

Interstate 10 was quicker, but they preferred the lonely back road, Route 9, that ran a few miles above the Mexican border, straight as a Euclidean line between low hills and the Chihuahuan desert scrub. It was almost midday, forty-four degrees and rising. Ahead, the two-lane road tapered away and dissolved into a mess of heat warp where buckled light showed smooth mirage puddles that evaporated at their approach. In an hour they had seen only three vehicles, all of them white pick-ups belonging to Border Patrol. When one passed, its driver raised his hand in grim salute. Beard drove, and Hammer sat hunched over his laptop, typing and muttering to himself, 'Fucking right they don't…that's better…but I haven't…try apologising, asshole…' Occasionally, he offered his companion genuine information. 'New York Times have cancelled…We had two jets for the fly-past, but that war hero with one leg at the Chamber of Commerce, the ex-pilot, knows everyone, so now we have seven.'

Beard drove at a steady fifty-five, the elbow of his steering hand cushioned comfortably on his paunch. In the States, it came easier, to drive at a lordly pace, with the big engine barely turning, almost silent. The country had lived en masse with the automobile longer than any other. People had wearied of the car as a racing device, or penis or missile substitute. They stopped at suburban crossroads and politely negotiated with glances who should go first. They even obeyed the fifteen-mile-an-hour limits around schools. At his untaxing speed, with the faded yellow lines rolling under the SUV, his thoughts turned obsessively, uselessly around the project. He held seventeen patents in the panels. If ten thousand were sold…and the conversion rate of water to hydrogen in ideal conditions like these €¦ a litre of water held three times the energy of a litre of gasoline. So in a smaller car with the right engine they could have made this journey with two litres of water, three wine bottles full €¦ They should have bought wine in El Paso, because the choice in Lordsburg was narrow €¦