Werner had responded to my toast by drinking some mineral water from a cut-glass tumbler. It had a lemon slice in it and ice too. It was as if he wanted to pretend it was a real drink. He sank down into an armchair and sighed. The black beard – now closely trimmed – suited him. He didn't look like a hippie or an art teacher, it was more formal than that. But formality ended at the neck. His clothes were casual, a black long-sleeve woollen pullover, matching trousers, rainbow-striped silk shin and shiny patent shoes. His hair was thick and dark, his pose relaxed: only his eyes were worried. 'It's Zena.' He reached across to get a coaster from the shelf and moved my wineglass on to it so it would not mark the polished side-table. Werner was house-trained.

Oh, no, I thought. Not an evening of talking about that wife of his, it was more than even a best friend should be expected to endure. 'What about Zena?' I said, trying to make my voice warm and concerned.

'More precisely, that damned Frank Harrington,' said Werner bitterly. 'I know what Frank means to you, Bernie, but he's a bastard. He really is.' He watched me to see if I would take offence on Frank's behalf, and he pinched his nose as he often did when distressed.

'Frank?' Frank Harrington was an amazingly successful womanizer. Linking Frank and Zena's names meant only one thing to me. Some years back, Frank and Zena had had a tempestuous affair. Like some nineteenth-century rake, he'd even set her up in a little house to await his visits. Then – the way I heard it – Zena got fed up with sitting waiting for Frank to find time for her. There was nothing of the nineteenth-century mistress about Zena. Since then I suspected that Zena had found other men, but always she returned to poor old Werner. In the long term he was the only one who would put up with her. 'Frank and Zena?'

'Not like that,' said Werner hurriedly. 'He's using her for departmental work. It's dangerous, Bernie. Bloody dangerous. She's never done anything like that before.'

'You'd better start at the beginning,' I said.

'Zena has relatives in the East. She takes them food and presents. You know…'

'Yes, you told me.' I reached for the little bowl of salted almonds but there were only a couple of broken pieces left buried under salt and bits of skin. I suppose Werner had eaten them while sitting here waiting for me and worrying.

'She went over there last week.' In German over there – 'druben' – meant only one thing, it meant the other side of the Wall. 'Now I've discovered that that bloody Frank asked her to look up someone for him.'

'One of our people?' I said guardedly.

'Of course. Who else would they be if Frank wants her to look them up for him?'

'I suppose so,' I conceded.

'Frankfurt an der Oder,' said Werner. 'You know what we're talking about don't you?' Despite the level voice he was angry now: damned angry, and somewhere in the back of his mind he was implicating me in this development of which I knew nothing, and preferred to know nothing.

'That's just speculation,' I said and waited to see if he'd say it wasn't.

'Why ask Zena?' His face was distorted as he bit his lip with rage and anxiety. 'He has his own people to do that kind of work.'

'Yes,' I admitted.

'It's Bizet. He's trying to reopen a contact string.'

'She'll be all right, Werner,' I said. I sympathized with Werner's anger but I'd been at the sharp end of operations. From the field agent's point of view it sometimes looked like good sense to send legitimate travellers such as Zena into these touchy situations. They are told nothing, so they know nothing. Usually they get away scot-free.

My apparent indifference to Zena's plight made him angrier than ever but as usual he smiled. He leaned back on the sofa and stroked the house-phone as if it was a pet cat. From the street outside there was the growling sound of the long-distance buses that had to turn into a narrow sidestreet to get to the bus terminal. 'I want you to do something,' he said.

'What do you want me to do?'

'Get her out,' he said. His fingers were twitching on the phone. He reached for the handpiece, called reception and, without asking me what I wanted to eat, told them he wanted the restaurant dinner sent round for us. He spoke rapidly into the phone ordering two portions of the very good salmon mousse and a couple of fillet steaks – one rare and one well done – and whatever went with it. Then he put the phone down, turned and looked at me. 'It's getting late,' he explained, 'the kitchen will close soon.'

I said, 'You don't really want the Department to bring her out, do you? From what you've told me, there's nothing to suggest she's in any kind of danger. I imagine Frank just asked her to make a couple of phone calls, or knock at a door. If I go rushing in to the office demanding a full-scale rescue attempt, everyone will think I've taken leave of my senses. And, quite honestly Werner, it might be putting Zena into a worse position than she is.' What I didn't add was that there was no chance at all that Dicky, or anyone in authority at the office, would countermand Frank's actions on my say-so. It sounded as if Frank had been made 'file officer' and his word would be law.

'How dare Frank ask Zena to help him?' Was that the real focus of Werner's rage: Frank Harrington? They'd never seen eye to eye. Even before Frank stole Werner's wife, he'd eased Werner out of the Berlin Field Unit. Now there was no way to convince Werner that Frank was what he was: a very experienced departmental administrator, and an archetypal 'English gentleman' who not only knew how to attract adventuresome young women but often fell prey to them.

And I could hardly tell Werner that his wife should have learned to stay away from Frank by now. So I said, 'When is she due back?'

'Monday.' He touched his beard. Glenn Gould finished playing but after a couple of clicks Art Tatum started. Werner liked the piano. In the old days he used to play at all the most rowdy Berlin parties. Seeing him now it was difficult to believe the things we had done in Berlin back in those days when we were young.

'She'll be all right,' I said.

Unconvinced by my reassurances he nodded without replying, and studied his glass of mineral water suspiciously before taking a sip of it. We sat for a moment in silence. Then he looked at me, gave me a little shrug and a smile and, noticing that my glass was empty, he got up and went to the refrigerator and brought more wine for me.

I watched him carefully. There was more to it – some other aspect to the story – but I didn't press him for more details. His anger had peaked. It was better for him to simmer down.

There was a tap at the door and – like some sort of well rehearsed cabaret act – a uniformed man from the reception desk helped a restaurant waiter to set up two folding chairs, a folding table, and an array of tableware. There were steaks and some spinach keeping warm on a chafing dish. The portions offish mousse, which the waiter insisted upon showing us, were under the heavy dome-shaped silver covers that are always needed to keep microscopic portions of food from escaping.

It wasn't until they'd gone and we were seated at the table eating the mousse that Werner mentioned Zena again. 'I love her. I can't help that, Bernie.'

'I know, Werner.' The salmon mousse was sinking into a puddle of bright green sauce; a pink, tilted slab with fragments of vegetable looking out of it, like passengers waiting for a rescue boat. I ate it quickly.

'So I worry,' said Werner, and he shrugged in a gesture of resignation. I felt sorry for him. It wasn't easy to imagine being in love with Zena. That some man might murder her, or join the Foreign Legion to escape her, was simple to envisage. But love her: no. 'She's the only woman for me.' He said it defensively, almost apologetically.