There were no military convoys on the road at Ghent and they made good time, reaching Ostend by seven o'clock in the evening. On the journey back they talked casually but guardedly – as did all Romer's employees, Eva now realised. There was a sense of solidarity that they shared, of being in a small elite team – that was undeniable – but it was really only a veneer: no one was ever truly open or candid; they tried to restrict their conversation to frivolous observations, bland generalities – specific times and places in their past, pre-Romer lives were never identified.

Morris said to her: 'Your French is excellent. First class.'

And Eva said: 'Yes, I lived in Paris for a while.'

In her turn she asked Morris how long he had known Romer. 'Oh, a good few years now,' he said and she knew from the tone of his voice that it would not only be wrong to ask for a more precise answer but that it would also be suspicious. Morris called her 'Eve' and the thought came to her suddenly that perhaps 'Morris Devereux' was no more his real name than 'Eve Dalton' was hers. She glanced over at him as they motored towards the coast and saw his fine features lit from below by the dashboard lights and felt, not for the first time, a dull pang of regret: how this curious job they were doing – regardless of how they were working towards the same end – consistently managed to leave them essentially divided and solitary.

Morris dropped her at her flat; she said good-night and climbed the stairs to her landing. There she saw Sylvia's blue square of card protruding just beyond the doorjamb. She slipped her key into the lock and was just about to turn it when it was opened from the inside. Romer stood there, smiling at her somewhat frostily, she thought, and at the same time she noticed Sylvia standing in the hall behind him, making vague panic gestures that Eva couldn't quite decipher.

'You've been a while,' he said. 'Didn't you take the car?'

'Yes, we did,' Eva said, moving through to their small sitting-room. 'It was raining on the way back. I thought you were meant to be in London.'

'I was. And what I learned there has brought me immediately back. Air travel, wonderful invention.' He moved to the window where he had left his bag.

'He's been here two hours,' Sylvia whispered, making a gruesome face, as Romer crouched down and rummaged in his grip and then belted it closed. He stood up.

'Pack an overnight bag,' he said. 'You and I are going to Holland.'

Prenslo was a nondescript small village on the frontier between Holland and Germany. Eva and Romer had found the journey there surprisingly tiring and taxing. They took a train from Ostend to Brussels, where they changed and caught another train to The Hague. At the main station in The Hague a man from the British Embassy was waiting with a car. Romer then drove them east towards the German border, except that he lost his way twice when he had to leave the main road to head crosscountry for Prenslo, and they spent half an hour or so doubling back before they found their way. They arrived in Prenslo at 4.00 a.m. to discover that the hotel that Romer had booked – the Hotel Willems – was locked shut and completely dark with no one prepared to respond to their bell-ringing, their shouts or peremptory knocking. So they sat in their car in the car-park until seven when a sleepy lad in a dressing gown unlocked the hotel's front door and they were finally, grumpily, admitted.

Eva had spoken little during the journey to Prenslo, deliberately, and Romer had seemed more than usually self-absorbed and taciturn. She felt there was something about Romer's attitude that irked her – as if she was being indulged, spoilt, that she should feel unusually privileged to be on this mysterious night journey with the 'boss' – and so she behaved dutifully and uncomplainingly. But the three-hour wait in the Hotel Willems's car-park and their enforced proximity had made Romer more relaxed and he had told her in more detail what they were doing in Prenslo.

On his brief trip to London Romer had learned that there was an SIS mission due to take place the next day in Prenslo. A senior German general in the Wehrmacht high command wanted to sound out the British position and response in the event of an army-led coup against Hitler. Apparently there was no question of deposing Hitler – he would maintain his role as chancellor – but he would be under the absolute control of the mutinous generals. After several preliminary encounters – to check security, to verify details – a unit of the British Secret Service based in The Hague had set up this first meeting with the general himself in a cafe at Prenslo. Prenslo was chosen because of the ease with which the general and his collaborators could slip to and fro across the border unremarked. The cafe in question was a hundred yards from the frontier.

Eva listened to all this attentively, with about three dozen questions clustering in her head. She knew she probably shouldn't air them but she didn't really care: she was both tired and mystified.

'Why do you need me for this?' she asked.

'Because my face is known to the SIS men. One of them is Head of Station in Holland – I've met him half a dozen times.' Romer stretched, his elbow bumping Eva's shoulder. 'Sorry – you'll be my eyes and ears, Eva. I need to know exactly what's going on.' He smiled tiredly, having to explain. 'It would look very odd to this fellow if he spotted me poking around.'

Another question had to be asked: 'But why are we poking around? Aren't we all "Secret Intelligence Service" people, at the end of the day?' She found the whole thing faintly ridiculous, obviously the result of some inter-departmental squabble – all of which meant she was wasting her time sitting in a car in a small town in the middle of nowhere.

Romer suggested they take a turn around the car-park, stretch their legs – they did so. Romer lit a cigarette, not offering her one, and they walked in silence a full circuit before returning to their car.

'We are not really SIS, to be precise,' he said. 'My team – AAS – is officially part of GC amp;GS.' He explained. 'The Government Code and Cipher School. GC ampersand GS. We have a… a somewhat different role to play.'

'Though we're all on the same side.'

'Are you trying to be clever?'

They sat in silence for a while before he spoke again. 'You've seen the stories we've been putting out through the Agence about disaffection in the upper ranks of the German army.'

Eva said yes: she remembered items about the threatened resignation of this or that high-ranking officer; denials that this or that high-ranking officer was being posted to a provincial command and so on.

Romer continued: 'I think this Prenslo encounter is all as a result of our stories from the Agence. It's only right that I should see what happens. I should have been informed from the outset.' In a gesture of his irritation he flicked away his cigarette into the bushes – a bit foolhardily, Eva thought, then remembered that at this time of the year the bushes would be damp and incombustible. He was angry, Eva realised, somebody was going to steal his credit.

'Does SIS know we're here in Prenslo?'

'I very much assume and hope not.'

'I don't understand.'

'Good.'

Once the sleepy lad had shown them to their rooms Eva was called into Romer's. He was on the top floor and had a good view down Prenslo's only significant street. Romer handed her a pair of binoculars and pointed out the key details in the panorama: there was the German border crossing with its striped black and white barrier; there was the railway line; there, a hundred yards back, was the Dutch custom-house, occupied only in summer months. Opposite was the cafe, the Cafe Backus, a large two-storey modern building with two petrol pumps and a glassed-in veranda with distinctive striped awnings – chocolate brown and orange – to cast shade. A new hedge and some tethered saplings had been planted around the gravelled forecourt; behind the cafe was a larger unpaved car-park, with swings and a see-saw at one side, and beyond it a pinewood into which the railway line ran and disappeared. The Cafe Backus effectively marked the end of Prenslo before Germany began. The rest of the village stretched back from it – houses and shops, a post office, a small town hall with a large clock and, of course, the Hotel Willems.