Had I read all the psychology books that Werner had on his shelf I might have started thinking that Zena was a manifestation of his desire for a daughter, or a reflection of childhood suspicions of his mother's chastity. As it was I just figured that Werner liked the dependent type and Zena was happy to play that role for him. After all, I was pretty sure that Zena hadn't read any of those books either.

But you don't have to read books to get smart, and Zena was as smart as a street urchin climbing under the flap of a circus tent. Certainly Zena could teach me a thing or two, as she did that evening. The apartment itself was an interesting indication of their relationship. Werner, despite his constant declarations of imminent bankruptcy, had always been something of a spender. But before he met Zena this apartment was like a student's pad. It was entirely masculine: an old piano, upon which Werner liked to play 'Smoke Gets in Your Eyes', and big lumpy chairs with broken springs, their ancient floral covers perforated by carelessly held cigarettes. There was even a motheaten tiger's skin which – like so much of Werner's furnishings – had come from the fleamarket in the abandoned S-Bahn station on Tauentzienstrasse. In those days the kitchen was equipped with little more than a can-opener and a frying pan. And glasses outnumbered cups by five to one. Now it was different. It wasn't like a real apartment any more; it was like one of those bare-looking sets that are photographed for glossy magazines. The lights all shone on the ceiling and walls, and the sofa had a scrape draped over it. Green plants, little rugs, cut flowers and a couple of books were strategically positioned, and the chairs were very modern and uncomfortable.

We were sitting round the dining table, finishing the main course of chicken stuffed with truffles and exotic herbs. Zena had told Werner what wonderful wine he'd chosen, and he asked her what she'd been doing while he was away.

Zena said, The only outing worth mentioning is the evening I went to the opera.' She turned to me and said, 'Werner doesn't like opera. Taking Werner to the opera is like trying to teach a bear to dance.'

'You didn't go alone?' asked Werner.

'That's just what I was going to tell you. Erich Stinnes phoned. I didn't tell him you were not here, Werner. I didn't want him to know you were away. I don't like anyone to know you're away.'

'Erich Stinnes?' said Werner.

'He phoned. You know what he's like. He had two tickets for the opera. One for you, Werner, and one for me. I thought it was very nice of him. He said it was in return for all the dinners he'd eaten with us.'

'Not so many,' said Werner glumly.

'He was just being polite, darling. So I said that you would be late back but that I would love to go.'

I looked at Werner and he looked at me. In some other situation, such looks exchanged between two men in some other line of work might have been comment on a wife's fidelity. But Werner and I were thinking other thoughts. The alarm on Werner's face was registering the fear that Stinnes knew Zena was alone because he had had him followed over there in the East Sector of the city. Zena looked from one to the other of us. 'What is it?' she said.

'The opera,' said Werner vaguely, as his mind retraced his movements from Berlin and across the dark countryside to the frontier and tried to remember any persisting headlights on the road behind, a shadow in a doorway, a figure in the street or any one of a thousand slips that even the best of agents is prey to.

'He sent a car,' said Zena. 'I started worrying when it was due to arrive. I thought it might drive up to the front door with a Russian army driver in uniform, or with a hammer-and-sickle flag on the front of it.' She giggled.

'You went to the East?'

'We saw Mozart's Magic Flute, darling. At the Comic Opera. It's a lovely little theatre; have you never been? Lots of people from the West go over for the evening. There were British officers in gorgeous uniforms and lots of women in long dresses. I felt under-dressed if anything. We must go together, Werner. It was lovely.'

'Stinnes is married,' said Werner.

'Don't be such a prude, Werner, I know he's married. We've both heard Erich talking about his failed marriage at length enough to remember that.'

'It was a strange thing for him to do, wasn't it?' Werner said.

'Oh, Werner, darling. How can you say that? You heard me saying how much I liked the opera. And Erich asked you if you liked opera and you said yes you did.

'I probably wasn't listening,' said Werner.

'I know you weren't listening. You almost went to sleep. I had to kick you under the table.'

'You must be very careful with Erich Stinnes,' said Werner. He smiled as if determined not to become angry with her. 'He's not the polite gentleman that he likes to pretend to be. He's KGB, Zena, and all those Chekists are dangerous.'

'I've got apple strudel, and after that I've got chocolates from the Lenotre counter at Ka De We, the ones you like. Praline. Do you want to skip the strudel? What about you, Bernard?'

'I'll have everything,' I said.

'Whipped cream with the strudel? Coffee at the same time?' said Zena.

'You took the words right out of my mouth,' I said.

'Stinnes is playing a dangerous game,' Werner told her. 'No one knows what he's really got in mind. Suppose he held you hostage over there in the East?'

Zena hugged herself, grimaced, and said, 'Promises, promises.'

'It's not funny,' said Werner. 'It could happen.'

'I can handle Erich Stinnes,' said Zena. 'I understand Erich Stinnes better than you men will ever understand him. You should ask a woman to help if you really want to understand a man like that.'

'I understand him all right,' Werner called after her as she disappeared into the kitchen to get the apple strudel and switch on the coffee-machine. To me in a quieter voice he added, 'Perhaps I understand him too bloody well.'

The phone rang. Werner answered it. He grunted into the mouthpiece in a way that was unusual for the amiable Werner. 'Yes, he's here, Frank,' he said.

Frank Harrington. Of the whole population of Berlin I knew of only one that Werner really disliked, and that was the head of the Berlin Field Unit. It did not portend well for Werner's future in the department. For Werner's sake I hoped that Frank retired from the service soon.

I took the phone. 'Hello, Frank. Bernard here.'

'I've tried everywhere, Bernard. Why the hell don't you phone my office when you get into town and give me a contact number.'

'I'm at List's,' I said. 'I'm always at Lisl's.'

'You're not always at Lisl's,' said Frank. He sounded angry. 'You're not at Lisl's now, and you haven't been at bloody Lisl's for the last two nights.'

'I haven't been in Berlin for two nights,' I said. 'You don't want me to phone you every night wherever I am, anywhere in the world, do you? Even my mother doesn't expect that, Frank.'

'Dicky says you left London without even notifying him you were going anywhere.'

'Dicky said that?'

'Yes,' shouted Frank. 'Dicky said that.'

'Dicky's got a terrible memory, Frank. Last year he took one of those mail-order memory courses you see advertised in the newspapers. But it didn't seem to make much difference.'

'I'm not in the mood for your merry quips,' said Frank. 'I want you in my office, tomorrow morning at ten o'clock, without fail.'

'I was going to contact you anyway, Frank.'

'Tomorrow morning, my office, ten o'clock, without fail,' said Frank again. 'And I don't want you drinking all night in Lisl's bar. Understand?'

'Yes, I understand, Frank,' I said. 'Give my best regards to your wife.' I rang off.

Werner looked at me.

'Frank reading the Riot Act,' I explained. 'Don't get drunk in Lisl's bar, he said. It sounds as if he's been talking to that fellow Henry Tiptree.'