Graves wasn't sure what it all meant. It was a control or alarm system of some kind, though - that much was clear. And if it was a control system, it required power. Power. As Graves watched, he had an idea -one possible way to beat the system that Wright was so carefully setting up. A chance, a slim chance…

`Do it,' he whispered, watching Wright. `Do it, do

`Do what?' Phelps asked. He was off the telephone now.

Graves did not answer. Wright had finished with the boxes. He turned some dials, made some final adjustments. Then he took the main plug in his hand.

`He's going to do it,' Graves said.

And he plugged it into the wall socket. Very plainly, very clearly, he plugged it into the wall.

`He's done it.'

`Done what?' Phelps said, angry now.

`He's connected his device to the apartment electricity.'

`So?'

`That's a mistake,' Graves said. `He should have used a battery unit.'

`Because we can turn off the electricity in that apartment,' Graves said. `Remotely.'

`Oh,' Phelps said. And then he smiled. `That's good thinking.'

Graves said nothing. His mind raced forward in exhilarating high gear. For the first time all day, he felt that he was not only keeping abreast of Wright but actually moving a few steps ahead. It was a marvellous feeling.

`Time?'

`Two fifty-one.'

And then, as he watched, Wright did something very peculiar. He placed a small white box alongside the two other metal boxes. And he closed the windows to the apartment. Then he taped the joints and seams of the windows shut.

Then he left.

`What the hell does all that mean?' somebody asked.

`I don't know,' Graves said. `But I know how we can find out.'

Wright emerged from the apartment house lobby wearing a grey suit. He carried a raincoat over his shoulder. Graves was waiting for him, along with two federal marshals carrying drawn guns.

Wright did not look surprised. He smiled and said, `Did your son like his gift, Mr Graves?'

Before Graves could reply, one of the marshals had spun Wright around, saying gruffly, `Up against the wall hands wide stand still and you won't get hurt.'

`Gentlemen,' Wright said in an offended voice. He looked at Graves over his shoulder. `I don't think any of this is necessary. Mr Graves knows what he is looking for.'

`Yes, I do,' Graves said. He had already noticed the raincoat. Nobody carried a raincoat in San Diego in August. It was as out of place as a Bible in a whorehouse. `But I want to know what time it leaves.'

`There's only one possible flight today,' Wright said. `Connexions in Miami. Leaves San Diego at four thirty.'

The marshal took Wright's shoulder wallet and handed it to Graves. The ticket was inside: San Diego to Los Angeles to Miami to Montego Bay, Jamaica. The ticket was made out to Mr A. Johnson.

`May I turn around now?' Wright asked.

`Shut up,' the marshal said.

`Let him turn around,' Graves said.

Wright turned, rubbing the grit of the wall from his hands. He smiled at Graves. `Your move.' In the smile and the slight nod of the head, Graves got a chilling sense of the profound insanity of the man. The eyes gave it away.

Wright's eyes were genuinely amused: a clever chess player teasing an inferior opponent. But this wasn't chess, not really. Not with stakes like these.

Death in 1.7 minutes, Graves thought, and he had a mental image of the prisoner twisting and writhing on the floor, liquid running from his nose in a continuous stream, vomit spewing out.

Graves realized then that he had mistaken his opponent for too long. Wright was insane. He was capable of anything. It produced a churning sensation in Graves' stomach.

`Tape him inside,' Graves said to the marshal. `I want to talk to him.'

The three of them sat in the lobby of the apartment building. It was the kind of lobby that aspired to look like the grossest Miami Beach hotels; there were plastic palms in plastic pots and fake Louis XIV furniture which, apparently out of fear that someone would want to steal it, was bolted to the imitation marble floor. Under other circumstances the artificiality of the surroundings would have annoyed Graves, but now it somehow seemed appropriate. By implication the room suggested that falsehoods were acceptable, even preferable, to the truth.

Graves sat in a chair facing Wright. The marshal sat diagonally facing both of them and the only exit. The marshal held his gun loosely in his lap.

Wright looked at the marshal and the position of the gun. `That's what it's all about,' he said, and smiled again. That insane smile.

`How do you mean?' Graves said.

Wright sighed patiently. `Do I confuse you?'

`Of course. That was your intention.'

`I doubt that I've confused you much,' Wright said.

`You've really done very well, Mr Graves. May I call you John?'

The condescending tone was unmistakable, but Graves merely shrugged. He glanced at his watch: 3:05.

`Very well, indeed,' Wright continued. `For the last month or so, John, I've had the feeling that you were a worthy adversary. I can't tell you how reassuring that was.'

`Reassuring?'

`I prefer to do things well,' he said. He took a slim cigar from a gunmetal case and lit it. `I mean elegantly, with a certain finesse. In a situation like this, one needs a proper opponent. I was immensely reassured that my opponent was you, John.' Wright sighed. `Of course, I have another opponent as well,' he said. `One totally lacking in finesse, elegance, and grace. The sad thing is, he thinks he's a statesman.'

`You mean the President?'

`I prefer to think of him,' Wright said, `as that man who rode the bench for so many years. Why did he ride the bench? Did you ever think of that? The answer is simple enough - because he wasn't a good player. He was inept. He was incompetent. He was a bumbling fool.'

`You feel strongly about him.'

`I feel strongly about his policies.'

`China?'

`Ten years ago,' Wright said, `if I asked you the name of the American President most likely to institute wage and price controls, welfare reform, and diplomatic relations with Communist China, would you have ever thought of this man? It's insane, what he's doing.'

`What about what you're doing?'

`Somebody has to stop him,' Wright said. `It's as simple as that.'

`I wouldn't call nerve gas a democratic method.'

Graves stared at him. `What are those metal boxes in the centre of the floor upstairs?'

Wright smiled. `Enough politics, eh?' He puffed on his cigar, billowing light. smoke. `Very well. Down to business.' A thought seemed to occur to him. `But if I tell you, how will you know it's the truth?'

`That's my job.'

`True, true. There are actually three boxes, as I'm sure you observed from your surveillance station across the street. I had to get an extension cord in order to place the boxes in clear view of the window.'

`Very thoughtful.'

`I felt you'd appreciate it,' Wright said. `The first box is a timer. It controls a rather intricate set of staging sequences for the equipment in the room.'

Graves took out a cigarette. His hands shook slightly as he lit it. He hoped Wright wouldn't notice - but that, of course, was wishful thinking. Wright would notice.

But Wright didn't comment on it. `The second box,' he said, `is an impedance and vibration sensor. There are contact points located around the room. On the door, on the floor, on the walls. Any excessive vibration - for example, a man walking on the floor of the room - will set off the gas. It's a commercial unit. I bought it last week.' He smiled then. `A friend made the purchase, so that you wouldn't be aware of it.'