Now he knew the reason for that evasion, he had developed a deep and abiding fascination with the castle. He’d even driven up there one night when they’d been moored a few miles upriver. He’d been too late to buy a ticket and take the tour, but he’d stood outside the ornately carved lintel of the main gateway his grandfather had entered sixty years before. How could anyone look at that grim facade and not sense the horrors those high narrow windows had witnessed? He imagined the stones held captive the screams and cries of hundreds of children. The very walls were a repository of pain and fear. Just looking at it made him sweat, the memories of his own agonies rising sharp and harsh as the day they were inflicted. The schloss should have been razed to the ground, not turned into a tourist attraction. He wondered if any of the guides on the pleasure boats that plied the gorge ever mentioned the recent history that had stained Schloss Hochenstein so indelibly. Somehow, he doubted it. Nobody wanted to be reminded of that part of the past. They wanted to pretend it had never happened. And that was why nobody had ever had to pay for it. Well, he was making the bastards pay now, that was for sure.

He rubbed away at the brass, his mind replaying the conversation he’d had in the beer garden with Heinrich Holtz. Well, not so much a conversation as a monologue. ‘We were the ones they called lucky,’ he’d said, his rheumy eyes flickering constantly from side to side, never settling on one thing for long. ‘We survived.’

‘Survived what?’ the younger man asked.

Holtz continued as if he hadn’t heard the question. ‘Everybody knows about the concentration camps. They all talk about the horrors inflicted on the Jews, the gypsies, the queers. But there were other victims. The forgotten ones. Me and your granddad, we were two of the forgotten ones. That’s because where we ended up was called a hospital, not a camp.

‘Did you know that German psychiatric hospitals held three hundred thousand patients in 1939, but only forty thousand were still alive in 1946? The rest died at the hands of the psychiatrists and the psychologists. And that’s not counting all the children and babies who were slaughtered in the name of racial purity. There was even one so-called hospital where they celebrated the cremation of the ten thousandth mental patient in a special ceremony. Doctors, nurses, attendants, the administrative staff, they all joined in. They all got a free bottle of beer to toast the occasion.