'You bastard! You cowardly bastard!'

Beard descended the stand as fast as he was able, then strode away. Even when he had reached the far side of the parade ground and was heading back towards the Texan-style barbecue, he could hear the diminishing cries, 'Cunt! Coward! Cheat! I'll get you!' Heads of upright citizens turned to look, and there were disapproving glances in Beard's direction too. Some minutes later, after a wrong turn, he found himself in the grand colonnade of green portable lavatories and slipped inside to make lingering use of one. When he came out and looked around, he saw Tarpin in the distance, right down on the highway, waving his thumb at the passing traffic.

Beard was late for his rendezvous with Darlene, but he was tired and hot, and there was much to think about, so he dawdled. Tarpin, not Aldous, was the lover whom Patrice could not shake off, and she made up a story to escape another black eye. But what had stopped the bullying was the thrashing Aldous delivered. Even if Beard had strangled Aldous with his bare hands, Tarpin would have stepped up to take the blame, such was the reach of his obsessive delusional state. Beard's past was often a mess, resembling a ripe, odorous cheese oozing into or over his present, but this particular confection had congealed into the appearance of something manageably firm, more Parmesan than Epoisses. He was reflecting cheerfully on this formulation – it reminded him that he was still peckish – and was in sight of the Texan barbecue when he felt his palmtop trembling in his pocket. Melissa, the screen told him. Calling before she turned in for the night. But when he put the phone to his ear he heard the sound of a car's engine and, faintly in the background, Catriona singing.

'Darling,' he said quickly, before she could speak. 'I've been trying to reach you.'

'We were on the plane.'

Running off with the conductor, taking his child, was his immediate thought. 'Where are you?' he said peevishly, expecting her to lie.

'We're just leaving El Paso.'

He paused to take this in. 'How can you be? I don't understand.'

'We're on our way. It's half-term, Lenochka is taking care of the shops and, as you know, Catriona and I have got something to discuss with you.'

'Like what?' Beard said, feeling nameless guilt. What had he done now?

She said, 'Someone called Darlene phoned to tell me you two are getting married. Before you do, your daughter and I would like a word.'

That. In memory the occasion was as vague as a half-forgotten dream, but he knew the moment, some weeks ago in the trailer bedroom. Darlene had not mentioned it since.

He said, 'Melissa, believe me, there's no truth in it.' As if by saying so he could make her turn back to London and leave his evening free.

She said, 'Hold on, I've got to take this exit…One other thing I want you to know before we meet. Terry.'

'Yes.'

'He doesn't exist. I made him up. It was a way of saving face, and it was stupid. It made things worse.'

'I see,' Beard said.

And he did. She had uninvented Terry, and now he would be expected to do the same for Darlene. He heard Catriona singing or shouting in the background.

Melissa said, 'We'll see you soon. And you belong to us.' She rang off.

He remained where he was, leaning against a pole that supported a loudspeaker. Thank God it was silent. Around him the site was emptying as the sun lowered and men came to the end of their shifts and headed for the parking lot. As he recalled it, he and Darlene had been making love after drinking one hot afternoon, and the air conditioning was at its highest setting, rattling like a madman at the bars of his cell. Seconds before he came, she cupped her hand around his balls and asked him to marry her and he had said, or shouted, yes. Perhaps the notion of such wild folly and abandon was what brought him on. How could he have meant it when he was already not married to Melissa? No one would believe a man at such a moment? The point was that Darlene had discovered his other life, and like the bold player she was, she was forcing his hand. Someone, or everyone, would be disappointed. Nothing new there.

Beard reached for his infrared car key, whose reassuring solidity seemed to contain all the miles he wanted to put between himself and Lordsburg. It would be sensible to slip away now, find lodgings along the interstate in Deming, avoid Darlene and Melissa all day tomorrow in order to concentrate on his world-historical event, then face them afterwards, together or separately. Anything but face them this evening. But as he turned to walk towards his car, he felt great sadness at losing the promised hour with Darlene. The old parliament of his selfhood was in uproarious division. An eloquent voice of experience rose above the din to suggest that denying himself a long-awaited release could be even more damaging to his concentration. He ignored this voice and continued walking. Sometimes a man had to make sacrifices, for science, for the well-being of future generations.

But then came deliverance. He had taken barely thirty steps when he heard his name called behind him. She had come out from under the Texan-barbecue awning into the thoroughfare just a hundred yards away, and was running towards him in a jiggling, splayed-arm manner, and he felt relieved. They would go straight to his motel room. The decision was out of his hands.

For reasons of her own, she did not ask him why he was heading in the wrong direction. They strolled companionably arm in arm down the boulevard of green latrines towards the parking lot. When they were there she thought it would be better if she left her car and came in his. He could think of no good reason why not, except that he would be bound to her company, tomorrow morning as well as tonight. That was surely what she had in mind. As he drove towards Lordsburg she slid her left hand across his lap, and she caressed him the whole way while she told him what she would do when they were indoors. He was in a trance, no other thought in his head, as he turned into the motel drive and pulled up outside his usual room. He went robotically to the office to check in. Soon they were reclining their excited naked bulks on cool sheets behind a double-locked door. Only ten years ago, when he still thought he could rescue himself with exercise, he would have been shocked by his own pneumatic form, by his concertina of chins, and by the ribbed contours of the woman he was stroking, and by the sweaty scent of newly cut grass that arose from armpits, groins and crooks of knees, heavily enfolded regions that rarely saw air or light. Yet everything was as thrilling as it had ever been. She was a kind and ingenious lover, who sucked and licked and teased and drew him wetly in, but when his moment came, he remembered to refrain from giving himself away in marriage.

Afterwards, they lay closely side by side. She lifted her weight onto one elbow and, gazing down on him fondly, played with the few tufts of hair that survived behind his ears. His eyes were closed.

'Michael?' she whispered. 'Honey?'

'Mm.'

'Did I ever tell you that I love you?'

'Yes…' He had been thinking, with strange lucidity of his old friend, the photon, and a detail in Tom Aldous's notes about the displacement of an electron. There might be an inexpensive way of improving a second generation of panels. When he was back in London he would blow the dust off that file. He said again, contentedly, 'Yes.'

'Michael?'

'Mm.'

'I love you. And d'you know something?'

'Mm.'

'You belong entirely to me and I'm never letting you go.'

He opened his eyes. Post-coitally, it troubled him, that women could not instantly discard their intimate pre-coital personalities, but lingered instead in an oppressive continuity of feeling. He, on the other hand, was luxuriating in the rediscovery of his unshareable core, in nurturing that private little part that was a man's closest approximation – was this ridiculous? – of a foetus. Ten minutes before he had felt he belonged to her. Now, the idea of belonging to anyone, of anyone belonging to anyone, was stifling.