'What is it?'

'Griffin must have sent this.'

'Aren't you the one who's jumping to conclusions now?'

'Maybe. But he didn't turn up that day, did he? Either because of road blocks… or because he never intended to.'

'Meaning?'

'Meaning he wanted me there. As a witness.'

'That makes no sense, Umber. No-one could have known Sally would take the Hall children to Avebury that particular morning.'

'God, no.' Umber put his hand to his brow and dropped the letter. 'They couldn't, could they?' He fell back in his chair. 'I swore I was finished with this when Sally died. The wondering. The theorizing. Constructing one house of cards after another out of frail suppositions. And then watching them collapse. She never stopped doing that. But I did. In the end, I was just so… weary of it… that I felt… weary of her.'

'You're not going to go maudlin on me, are you?'

Umber's answer was a long time coming. 'I'll do my best not to.'

'I need your help.'

'My help?'

'To crack this.'

'It can't be done, George.'

'Which – the cracking or the helping?'

'Both. Contrary to what Junius says, it is too late.'

'We won't know that till we try.'

'We?'

'I could have gone on drawing my pension and tending my allotment happily enough, you know. But not now. Not now I've been reminded of what I did wrong all those years ago.'

'And what was that?'

'I gave up. I stopped looking. I wrote the little girl off.'

'You didn't have much option.'

'We'll see about that.'

'I can't get involved, George. Not now. Not after… putting it all behind me.'

'What exactly have you done with the past twenty-three years, Umber?'

'This and that.'

'I came here expecting to find you'd sent me this letter because you blamed me for Sally's death.'

'Sorry to disappoint you.'

'You disappoint yourself. You know you do. You live in a dingy apartment scraping by on odds and sods of casual tour-guiding. Is that how you plan to go on for the next twenty-three years?'

'Something will turn up.'

'It just has. Your big chance – and mine – to set things right.'

'You're kidding yourself, George. It's a fool's errand. Besides, you're the detective. What do you need me for?'

'Younger pair of legs. Keener pair of eyes. And the last word on Junius. That's what I need you for.' Sharp drained his glass. 'I'll cover your travelling expenses if that's what you're worried about.'

'Police pensions must be more generous than I thought.'

'I just don't want you to have any excuse for turning me down.'

'I don't need an excuse.'

'That a fact? Then, tell me, why are you trying so hard to find one?'

'I'm not going back with you, George.'

'I'll give you twenty-four hours to think it over.'

'It won't make any difference.'

'No. It won't.' Sharp slid the letter back into its envelope. 'Because you already know what you're going to do.' He smiled at Umber. 'You just can't bring yourself to admit it.'

Half an hour later, Umber was on the number 24 tram, trundling north through the darkened streets of Prague – streets Sally had never trodden. Their wanderings had taken them to most of the capital cities of Europe, but never this one. That, he knew, was one of the reasons he had come to Prague – and had stayed. He opened his wallet and took out the snapshot of her he always carried with him. It was the only picture he had of her. The flood had claimed the others. All that was left to him was this spare passport photograph from nearly twenty years ago.

Her dark, shoulder-length hair cast part of her face in shadow, accentuating her high cheekbones and making her look gaunt and troubled, whereas in his mind's eye she appeared neither. He remembered her smile so very clearly. But she had seldom smiled for the camera. Somehow, she had never quite trusted herself to.

He put the picture away again and looked at his own, ghostly reflection in the window. 'What do you want me to do, Sal?' he asked her under his breath, watching his lips shape the words. 'Just tell me. That's all you need to do. That's all you ever needed to do.'

There was no answer. There could never be. It was too late for that.

He dreamt of Sally that night, for the first time in a year or more. They were in the tiny flat in Barcelona that had been their first home together. But he could not understand why she was there. 'They told me you were dead,' he said, over and over again. She wrapped her arms around him and kissed him on the neck. 'Me, dead?' she whispered into his ear. 'That's such a silly idea.'

He was woken by the telephone. Opening his eyes, he saw that it was light outside. According to his bedside clock, it was nearly ten. He had lain awake for what felt like hours before falling asleep, but sleeping this late in the morning was nonetheless a surprise.

He grabbed the telephone, wondering if it would be Sharp badgering for an answer, then realized it could not be because he had not given him this number.

'Halo?

'Dobre rano.'

'What can I do for you, Marek?'

'Not for me, brother. For Ivana. She needs you to cover Tuesday.'

'Ah… Tuesday?'

'Jo. Day after Monday. Day before Wednesday. I can put you down for it?'

'I'm not, er… too sure I…'

'I need a decision, like, right now.'

'Then it's no.' Sharp was right, of course, damn him. There never had been any doubt about what Umber was going to do. 'Not Tuesday. Not any other day. For the foreseeable future.'

Travelling light and at short notice was one luxury David Umber could well afford to indulge. When Sharp proposed a Sunday morning departure, he did not demur. Nor did he try to hold Sharp to his whisky-fuelled offer of paying for the journey. But the retired policeman seemed oddly determined to put his pension money where his mouth had been.

'I'll make all the arrangements.'

'There's no need. I can -'

'Leave it to me.'

'All right. I will.'

'I'll pick you up at eleven.'

'What time's the flight?'

'Just be ready at eleven.'

'I can make my own way to the airport. If you're worried I'll change my mind, I can -'

'Be ready at eleven.'

And so the telephone conversation had ended. It was a long way from being the last telephone conversation Umber had that day, however. When Ivana heard he was quitting Jolly Brolly, she rang to congratulate him on landing a full-time job, the only possible explanation for his conduct that had occurred to her. From her the news spread to his other friends that he was in fact going away for a while, prompting various farewell calls and good-luck messages. He assured one and all that he would be back before long. But nobody seemed quite to believe him.

'You think because things have gone bad for you here they will go good for you in England?' Ivana asked in her second call of the day. She had persuaded herself that the parting from Milena was what was driving him away and assurances from Umber to the contrary were futile.

'I don't think that.'

'You remember. Dostat se z blata do louze.' It was an old Czech saying. Out of the mud into the puddle.

'I'll remember,' said Umber.

And so he would.

Several loud blasts on a horn announced Sharp's arrival at dead on eleven o'clock the following morning. Umber looked out of the window of his flat expecting to see a taxi waiting for him below and hoping for Sharp's sake that he had agreed the fare beforehand.