‘Is that the secret? Paavo Falenius’s money?’ Eusden remembered the cache of pre-war Finnish currency at Nydahl’s apartment in Copenhagen. ‘Ever heard of Hakon Nydahl?’

‘Yes.’ Timo looked surprised. ‘I have. He was one of our customers. A very special customer.’

‘In what way?’

‘His account was managed personally by the chairman, Eino, Paavo’s son, Arto’s father. Everything relating to it had to be referred to Eino. The only other customer who ever got treated like that…was Tolmar Aksden.’

‘So, they’re all tied together in some way. Hakon Nydahl, Tolmar Aksden and the Faleniuses.’

‘Yes.’

‘And what is the connection?’

‘Like Osmo said, we don’t know. But…’

‘But what?’

Osmo interrupted in Finnish before Timo could reply. There was a flurry of exchanges between the two brothers. Though Eusden could not understand a word, he had the impression that an argument they had had several times before was being repeated. Eventually, it petered out. And Osmo made a gesture with his hands that looked like a concession of kinds.

‘There is a man I know, Mr Eusden,’ Timo said, slowly and carefully. ‘His name is Pekka Tallgren. Twenty years ago he was a history lecturer at Helsinki University. He planned a book on revolutionaries active in Finland before the First World War. Lenin, obviously, but there were many others, mostly Russian. Tallgren came to us – to Saukko – for information about Paavo’s links with these people. Paavo had been dead many years by then, of course. Tallgren said he had evidence that Paavo had provided several revolutionary groups with funds. He asked if we had records of these dealings. We referred his request to the chairman. Arto had only recently taken over the chairmanship from his father. He was… embarrassed, it seemed to me. He told us Tallgren was to be given no information of any kind. Tallgren soon realized he was getting nowhere. He stopped asking his questions.’

‘What happened to his book?’

‘It was never published. Several years later, after I retired, I met Tallgren in Observatory Park. He was not in a good state. He told me his publisher cancelled his book contract soon after he approached us. Then one of his female students complained he had molested her. He denied it, of course. He was suspended. He started to drink heavily. He never went back to the university. In the end, even though the student later withdrew her complaint, he was dismissed.’

‘Arto Falenius arranged all that?’

‘Or Eino did. He was still a powerful man even after he handed the chairmanship over to Arto. Tallgren told me it was when he asked Arto about one revolutionary in particular that his troubles began.’

‘Who was that?’

‘I can’t remember the name. But Tallgren will remember for sure.’

‘You know how I can contact him?’

‘I felt sorry for him, Mr Eusden. So, I gave him a little money and helped him find somewhere decent to live. He sobered up, I’m glad to say. Later, I…recommended him for a job. Do you know Suomenlinna?’

‘No. What is it?’

‘A small group of islands out in the harbour. The Swedes constructed a fortress called Sveaborg on them in the mid-eighteenth century to defend their eastern frontier against the Russians. Later, the Russians took it over. And, later again, we Finns. It’s a tourist attraction now. It includes a museum where you can learn about the history of the fortress. That’s where I helped Tallgren get his job. He works as a curator in the Suomenlinna Museum. And he lives out there, in an apartment block on one of the islands. I think… if I asked him… he would speak to you. Yes, I think he would.’

‘Then, ask him.’

‘You’re sure you want me to?’

Eusden nodded. ‘I’ve never been more sure of anything in my life.’

FORTY-FOUR

It was gone midnight when Eusden reached the Market Square pontoon, but a couple more ferry crossings to Suomenlinna were still to be made. The cold had become more intense than he had ever experienced. The sea ice moaned and creaked. His breaths were plumes of frost in the still, deeply sub-zero air.

The few passengers, Suomenlinna residents bound for home, huddled in the cabin as the ferry chugged out through the broken skin of ice on its channel across the harbour. Eusden sat staring at their reflections in the windows, including his own – gaunt, drained and hollow-eyed. He spun Lund’s phone in slow circles on the table, wondering if he should call Gemma and tell her… But since he did not know what he should or could tell her, he made no call.

He scrolled idly through Lund’s contacts list. Tolmar Aksden was there; so, too, was Arto Falenius. He was tempted to call one of them – or both. He wanted them to know, even though he was well aware it was better they did not, that he was coming after them. They had overreached themselves. This time, he willed them to understand, there would be a reckoning.

The tower above the main gate of the fortress loomed through the chill mist that hung over Suomenlinna as Eusden stepped ashore. A single figure was waiting on the quay, wrapped in a parka with a huge Arctic-standard hood. ‘Richard Eusden?’ he enquired, pulling off a mitt to offer his hand. ‘I’m Pekka Tallgren.’ They shook. ‘Cold night for a boat trip, no?’

‘Thanks for agreeing to talk to me, Mr Tallgren.’

‘Call me Pekka, Richard. OK?’

‘OK.’

‘I bet you’re thinking: why does the crazy man live out here on this frozen island?’

‘Timo said you work here.’

‘I do. But sometimes… it feels a bit like Alcatraz, with San Francisco across the bay. Anyway, let’s not stand here, freezing our balls off. I brought the car with me.’ Tallgren turned and led the way towards a tiny old Fiat. ‘It’s not far to my place. But everywhere’s a long way on a night like this.’

‘Sorry it’s so late.’

‘Don’t worry. I don’t sleep so good.’ They clambered into the car. Tallgren threw back his hood, revealing a bearded, heavy-featured face. He started the engine and skidded away along a sparsely gritted strip through the surrounding blanket of snow and ice. ‘I’ve got interested in astronomy since I came here. You can see so much more this far from the lights of the city. Not when it’s like this, of course. You’re not keeping me from my telescope, that’s for sure.’

They rumbled over a narrow bridge to an adjoining island and turned left past a high stone wall. ‘How long have you lived here, Pekka?’ Eusden asked.

‘Nine years. Some exile, hey? But, truthfully, I like it. I’m near Helsinki but not in it. That suits me. It keeps my memories at just the right distance. Timo told you all about my… troubles, no?’

‘Yes. He did.’

‘He helped me a lot. More than he needed to. So, I owe him. Which is lucky for you. I don’t normally talk to anyone about Saukko.’

‘I know. I’m grateful.’

‘Maybe you shouldn’t be. Knowing this stuff… can be unhealthy.’

They crossed a second bridge to a further island and slewed to a halt in a courtyard flanked by barrack blocks converted into apartments. Most of the windows were in darkness and a profound silence closed about them as they climbed from the car.

‘Welcome to my world, Richard,’ said Tallgren.

The apartment was small and felt smaller still thanks to the crammed bookshelves lining every spare wall and the piles of books and papers that had overflowed on to the floors beside them.

Stripped of his mitts and parka, Tallgren looked just what the domestic disorder might have led Eusden to expect: untidily dressed, grey hair overdue for a trim – a middle-aged academic content in his own shambolic environment. Except that he was an academic no longer.

‘I set some coffee going before I left,’ Tallgren said as Eusden hung up his coat in the tiny hallway. ‘You want some?’

‘Fine.’ Eusden would have preferred a stiff drink, but he knew better than to ask for one.