I did some thinking while I finished taking my rubbings. It definitely wasn’t her leg she was looking for because she thought that was probably buried in the south of France. And it wasn’t the Poles from the château because she kept looking at British war graves more than any other nationalities. I made a deduction, which is what it’s called when you rule out options to try to find an answer to a problem, just like in maths when you eliminate the common terms that you can on either side of an equation, to help you boil it down to what they’re really looking for.
 
 ‘Are you looking for Ben?’ I said.
 
 ‘Yes,’ she replied. ‘Still. After all these years.’
 
 ‘So do you think there’s a chance he could be buried on the island?’
 
 ‘It’s a slim one, but it’s not out of the question. I’ve looked everywhere else and eliminated most of the other more likely possibilities over the years.’
 
 ‘Do you think that’s him?’ I asked, pointing to the grave of the unknown airman.
 
 She shook her head. ‘The date’s not far off, but it’s still wrong again. You know, Finn, I’ve managed to find so many others. But not him.’
 
 ‘There are some more war graves in the cemetery at Saint-Martin. We can go and look there tomorrow if you like.’
 
 She laughed. ‘I’m not sure trailing you around cemeteries looking at graves is exactly what your parents had in mind when they agreed to leave you in my care.’
 
 ‘It’s OK. I like cemeteries. They’re peaceful. And we are getting fresh air, so Mum and Dad will be pleased about that. So it will be fine if we go to Saint-Martin tomorrow.’ I repeated the bit about Saint-Martin because I’d noticed she hadn’t said yes. I thought she might be giving up her search. She probably doesn’t have as much persistence as I do. That’s one thing Dad says I definitely have.
 
 She still didn’t reply, and she seemed a bit tired, so before we cycled home again, we went and sat down on a bench in the shade of a tree.
 
 ‘What happened to the rest of the Poles after they left the château?’ I asked.
 
 ‘Well now, that’s a very good question,’ she said. ‘As you know, Marian Rejewski and Henryk Zygalski made it to England. Gwido, Maksymilian and Antoni weren’t so lucky though. We’d heard that the three of them were betrayed by their guide and captured by the Nazis as they tried to cross into Spain. The British Intelligence Services were still in touch with their French counterparts and heard from Bolek that the men had all been interrogated by the Gestapo. They’d realised that if they denied everything they’dsimply be executed. So they confessed that they’d been working as codebreakers but managed to convince the Germans that they’d been beaten by the complexity of Enigma once the additional rotors had been implemented. They gave away just enough detail to save their lives, but still kept the secret of the French and British success.’
 
 She sat up a bit straighter. ‘You know, Finn, Winston Churchill said the Bletchley codebreakers were “the geese who laid the golden egg and never cackled”. Do you understand what that means?’
 
 I thought about it. I know the story about the goose and the golden eggs because it’s in a book I used to read when I was younger. ‘Yes, I think so,’ I said. ‘Even though you were doing something very important, you never talked about it?’
 
 ‘Exactly. Well, Gwido, Maksymilian and Antoni never cackled either, even when they were put under the immense pressure of interrogation. Imagine having that presence of mind. They protected us all.’
 
 ‘So after they’d been questioned, what happened to them next?’
 
 She slumped against the back of the bench again. ‘They were sent to a concentration camp called Sachsenhausen.’
 
 I thought maybe she’d gone to sleep because she went quiet then and closed her eyes. But after a few moments she opened them again. ‘Do you know about the concentration camps in the Second World War, Finn?’
 
 ‘Yes. I did a project about them, even though Dad didn’t really want me to. But I haven’t heard of Sachsenhausen.’
 
 She sighed. ‘It was the first one created by Himmler when he was appointed Chief of the German Police. He used it as a model for those that followed, and it was especially brutal. Many political prisoners were sent there, especially from Poland and Russia. They were treated appallingly and many of them were executed. Those that survived were made to work in the brickworks there, and a munitions factory. But you know, Finn, even from there the Poles managed to get a fewmessages out. Some of the work they were forced to do made them realise the Germans were building something big, some sort of secret weapon. The metal cases they were working on were being sent to a place called Peenemünde, in the far north of Germany on the Baltic Sea. A team of Polish engineers who’d been interned in the camp were sent there to work on the project and they managed to smuggle out a message, via a Resistance network, telling the Allies to look closely at what was happening in that location.’
 
 ‘And whatwashappening?’
 
 ‘The Germans were developing a new weapon there. It was the first ever liquid-propellant rocket, called the V-2. It could be fired from Germany and hit Britain. A whole new way of waging war. The intelligence that had been smuggled out helped the Allies launch bombing raids against the facility at Peenemünde. And while they didn’t manage to destroy it completely, they certainly hindered operations.’
 
 We both sat quietly for a bit while I thought about that. Then I said, ‘But you haven’t told me yet what happened to Gwido and Maksymilian and Antoni. Were they still at Sachsenhausen?’
 
 ‘Yes,’ she said. ‘And there were Allied bombing raids there as well. Antoni was killed in one of them.’ She looked at me for a while. ‘You know, Finn, I’m not sure these are appropriate topics of conversation. They are very hard to talk about.’
 
 ‘I know,’ I said. I repeated something Dad had said to me when I was doing my concentration camp project. ‘Sometimes the world is a very hard place. Sometimes people do terrible things. But we need to know about them so we can try to make sure history doesn’t repeat itself. We need to make sure they are never forgotten.’
 
 She made a surprised expression, with wide eyes and raised eyebrows. ‘You’re absolutely right about that.’
 
 ‘So Antoni was killed,’ I said. ‘That was very sad. Especially when he’d been so brave in the interrogations. But what about Gwido and Maksymilian?’ I thought she was procrastinating,which is another word Dad uses quite often when I’m busy doing something and he wants me to do something else.
 
 ‘Gwido Langer and Maksymilian Ciezki survived Sachsenhausen. The camp was eventually liberated by the Allies when the war ended, and they were brought to Great Britain to join their colleagues in the Polish Intelligence Service, which was still operating out of London at that time. But their return to safety and freedom at long last wasn’t what it should have been. Bolek – the head of the French intelligence bureau – had made a report, you see. Fingers were being pointed at him for the Poles not getting out of France in time and he wanted to shift the blame elsewhere. So he said Gwido was the one who’d been indecisive and hadn’t had the nerve to move. His report made Gwido, as Chief of the Polish Cipher Bureau, responsible for the deaths of those of his men who’d been lost. When Gwido and Maks arrived in London, they were given a chilly reception by their compatriots. And then they were sent, in some disgrace, to a signals station in Scotland, where more Polish servicemen were stationed.’ She was quiet again for a few moments, then she went on.
 
 ‘Maksymilian never made it home to Poland. He died in England in poverty, living on government assistance. Gwido died in Scotland a couple of years after arriving there, aged just fifty-three. I think his health had been badly affected by his interrogations and his time at Sachsenhausen. And he was consumed by a sense of betrayal, by shame and bitterness at how it had all turned out, feeling he and his team had been cast off by the French and British once they were no longer of use to them. He left word that he wanted to be buried with other Polish servicemen, in the corner of a cemetery in Scotland, because he didn’t feel worthy of going home to Poland.’