She watched him as he read the menu. Was she in love with him? Was that the explanation of the shock? Or was it more fundamental, was she becoming unbalanced?

Any feeling she had for Harry was not like the stable and enduring love she had for her home, her children and her husband. Harry's absence from her life had not caused her the heart-rending agony that separation from her family had brought, an agony from which she never escaped. That old love for Harry was something quite different, separate and not in conflict with it. But she could not help recalling that the love she'd once had for Harry was electrifying. It had been illicit and more physical than anything she'd known with Bernard. Sitting here across the table from Harry made her remember vividly the way that not so long ago even a glance from him could be arousing. 'I beg your pardon?' she said absently as she realized he was expecting an answer from her.

'I had it the other night,' he said. 'It was rather good.'

'I'm sorry. My mind was wandering.'

'The Kabinett is always the driest, at least I've learned that in the time I've been here.'

'Wonderful,' she said vaguely and was relieved when he waved to the waiter and ordered a bottle of some wine he'd discovered and liked. His German was adequate and even his accent was not too grating upon her ear. She looked around the restaurant to be sure there was no one there she recognized. It was crowded with foreigners: the only ones who had access to the sort of foreign money with which the bill had to be paid.

'My money comes in Western currency. I eat here all the time,' he told her.

Could he, by any chance, be an emissary from London Central? No. This was not a man whom Bret or Sir Henry would regard as right for the tricky job of intermediary. And yet a paramour would make the perfect cover for a London contact. If that was his role, he'd reveal it soon: that was how such things were done. She'd wait and see what happened: meanwhile she would be the perfect communist. 'So what do you suggest we eat?' she asked.

He looked up and smiled. He was so happy that his elation affected her. 'Steak, trout or schnitzel is all I ever order.'

'Trout then; nothing to start.' And then another thought struck her like a bombshell: could he be Moscow's man? Very very unlikely. At that first encounter in London he'd admitted having no work permit. Had she phoned Immigration they would have pounced on him. Wait a minute, think about it. It was his vulnerability to officialdom that made her decide not to have him officially investigated. That and the fact that Bernard might have started asking questions about him. She lived again through that first encounter on the railway station, step by step, word for word. His 'niece' talked to Fiona and then ran away. It could have been a set-up. There was nothing in that meeting that could not have been previously arranged.

'Fiona,' he said.

'Yes, Harry?'

'I love you desperately.' He did love her: no one could feign adoration in the way that she saw it in his eyes. But, said the neurotic, suspicious and logical side of her, being in love did not mean that he couldn't have been sent by Moscow. 'I know everything about you,' he said suddenly, and she was alarmed again. 'Except why you like Der Freischütz. I know every mini-quaver of it by now. I can take Schoenberg and Hindemith, but can you find me ten minutes of real melody in that whole darn opera?'

'Germans like it because it is about a completely unified Germany.'

'Is that what you want: a unified Germany?' he asked.

Red lights flashed. What was the official line on unification? 'Only on the right terms,' she said guardedly. 'What about you?'

'Who was it who said that he liked Germany so much that he preferred there to be two of them?'

'I'm not sure.'

He leaned forward and confidentially said, 'Forget what I said: I'm just crazy about Der Freischütz; every little demi-semi-quaver.'

London. October 1983.

It was two o'clock in the morning. Bret was in his Thameside house, sitting up in bed reading the final few pages of Zola's Nona. Influenced by Sylvester Bernstein, Bret had discovered the joy of reading novels. First Sylvy had lent him Germinal and now Bret – always subject to deep and sudden passions – had decided to read every volume of Zola's twenty-volume cycle. The phone rang. He let it ring for a long time, but when the caller persisted he reached for it. 'Hello?' Bret always said hello; he didn't believe in identifying himself.

'Bret, my dear fellow. I do hope I didn't wake you.'

I'm reading a superb and moving book, Sir Henry.'

'As long as you're not in the middle of anything important,' said the D-G imperturbably. 'I know you are something of a night owl. Anyway this won't wait, I'm afraid.'

'I understand.' Bret put the book aside and closed it regretfully.

'Special Branch liaison came through to me at home a few minutes ago. Apparently a young woman, English by all accounts, walked into the police station in Chichester and said she wanted to talk to someone in our line of business.'

'Oh, yes, sir,' said Bret.

'You're yawning already, of course. Yes, we've seen a lot of those in our time, haven't we? But this lady says she wants to tell us something about one of our people in London. She's mentioned a man whose wife recently left him. Furthermore she met that wife recently in Berlin. You're still with me, are you Bret?'

'Very much with you, Sir Henry. Met her? By name? Mentioned her by name?'

'Apparently: but things usually become a bit vague by the time reports come word of mouth all the way to me. Very very urgent she said it was: someone was about to be killed: that kind of thing. But yes the name was given. Special Branch thought they should check to see if the name rang a bell with us. The night duty officer decided it was important enough to wake me up. I think he was right.'

'Yes, indeed, sir.'

'A Special Branch inspector is bringing this lady up to London. She gave her name as Mrs Miranda Keller, née Dobbs. No joy there of course, the German telephone books are full of Kellers. I wonder if you would be so kind as to talk to her? See what it's all about.'

'Yes, sir.'

'Special Branch have that estate agent's office in Kensington. The house behind the Sainsbury supermarket. You know it, I'm sure.'

'Yes, sir.'

'They will be there in under the hour.'

'I'll get going immediately, sir.'

'Would you really, Bret. I'd be so grateful. I'll be in the office tomorrow. We can talk about it then.'

'Yes, sir.'

'Of course it may be nothing at all. Nothing at all.'

'Well, I'd better hurry.'

'Or it could be our old pals getting up to naughty tricks. Don't take any chances, Bret.'

'I won't, sir. I'd better get started.'

'Yes, of course. Goodnight, old chap. Although for you I suppose it would be good morning.' The D-G chuckled and rang off. It was all right for him; he was going back to sleep.

Mrs Miranda Keller was thirty-six years old, and the wig she was wearing did not make her look younger. It was almost four o'clock in the morning and she'd endured a long car ride through the pouring rain to this grand old house in Kensington, a shabby residential part of central London. Miranda let her head rest back upon the frayed moquette of the armchair. Under the pitiless blue glare of the overhead lighting – which buzzed constantly – she did not look her best.

'As I told you, we have no one of that name working for us,' said Bret. He was behind a desk drinking stale black coffee from the delicate sort of china ware that is de rigueur in the offices of earnest young men who sell real estate. With it on the antique tray there was a bowl of sugar and a pierced tin of Carnation milk.