It was as if I'd had a blood transfusion. Or perhaps it was just the warm June sun on my brow after the longest, coldest winter in Scottish records. Rising with first light, strolling through Kelvingrove Park down the winding paths lined with new-minted leaves. Then across to the Western Baths Club to carve out spluttering lengths in the great echoing hall. Something was making my blood sing, as though – and I scarcely dared hope – I'd finally emerged from festering anger and self-pity.

They say the best blades are toughened by heat and hammering. Time and again over the past eight years I'd been fired in the furnace, pounded flat, and quenched. In blood. I was at last rising from the dust of the African campaign, the damp of the Ardennes, and the soul-shrivelling scenes from the death camps. Last month, in merry May, a line had been drawn in my personal ragged history when the death penalties had been carried out on the Nazi overseers of Ravensbrück. It was as if the hangman had performed an exorcism with every pull on his lever.

Or maybe it was the couple of sessions I'd had with a head doctor. Sam had cajoled me into seeing the husband of an old pal of hers: Dr Andrew Baird. There was no couch, no tweed and pipe, no inkblot tests or unravelling of my childhood. Baird – about my own age, intense and engaging – was even prepared to come to me. We sat in Sam's library, each nursing a glass of whisky, while he gently plied me with questions.

'When the war ended you were commanding a company of Seaforth Highlanders?'

'I'd been given Acting Major. We'd fought our way from Normandy to Bremen.'

'But you didn't come home with them?' he said casually, taking off his specs and cleaning them on his tie.

'Sam's briefed you well.' I smiled. 'No, I studied languages at Glasgow before the war, French and German. The top brass found out and I was assigned to sift Nazi goats from Wehrmacht sheep and send the former off to military courts.'

'Harrowing?'

'They weren't nice people. They'd done bad things.'

'You saw?'

'Yes. Belsen.'

He nodded. 'When did they let you come home?'

'November '45.'

'Back here?'

I shook my head. 'Couldn't face it. All too ... normal, somehow. I just needed time off. I was demobbed in London and hung around there for a few months.'

'Doing?'

'Drinking mainly.' I hefted my glass and swilled its golden contents. 'Then I began pulling myself together. Started getting work as a reporter.'

'When did the nightmares start?'

'Oh, mid '45, I suppose. It figures, doesn't it?'

'Yes. Very typical. I'm seeing a lot of men like you, Douglas. They called it shell shock in the Great War. Now it's combat stress, or battle fatigue. But you know what I'm talking about?'

'I was fine during the battles, Doc.' I smiled again.

'That's how it works. We're only just appreciating how deep the trauma runs when a man is subjected to horror on a continual basis, such as war, or recurring acts of violence. Seems like you received more than your fair share.'

We met for a second time a week later and I told him about my recent experience of getting dragged into the hunt for the war criminals who'd used Scotland as a staging post to South America.

'And this January you ended up in Hamburg with Samantha. Back in uniform?'

'Ridiculous, wouldn't you say?'

'Asking a lot of a chap, I'd say. And the nightmares began again.'

'They never really stopped.'

'While the drinking got worse.'

'Never really stopped either, Andrew. But, yes, I suppose I was hitting the bottle a bit harder.'

'Is that when you ...?'

'Cracked up? I'm not afraid of the term. I've seen it in some of my men. I was exhausted. We'd been in Hamburg for weeks. A city of rubble. An ice city. Minus thirty degrees. I was questioning the same swine about the same foul deeds. An endless loop. Into the bargain, I lost a good man. A soldier. Between the booze and the ...'

'Trauma?'

'Is that what it was? I suppose so. But, yes, I fell apart for a bit. But I'm through that, Doc. As you can see.' I raised my glass in a toast.

He looked at me over the top of his specs. 'So it seems, Douglas. So it seems. Good for you. But I must warn you that even the toughest finds it hard to shake it off completely. It could take a while.'

'Months?'

'Years. They saw a lot of this after the last war. Some chaps never got it back together. Nothing to be ashamed of. It's like a leg wound that never quite heals.'

'That's comforting. Are you saying I could crack up again?'

'Let's say you should avoid situations that could trigger a relapse.'

'Makes sense. No more chasing war criminals. I'm all for the quiet life.'

He gave me one of his looks again. 'That's another thing. Douglas, you've been in action of one sort or another since you went to France in '39 with the British Expeditionary Force. That's nigh on eight years of fighting. And before that you had a tough job as a Glasgow policeman. It is astonishing what the mind can get used to. How many jolts it can take. It becomes natural to the point where the mind misses it when things are quiet. Begins to need it.' He paused. 'Do you get bored easily?'

'Wish I had the chance!'

'Watch out for it when you do. Let's keep in touch, Douglas.'

I promised I would, but in truth I was feeling more and more that I was back in control of my life. Sure, grief and anger still rose in me like bile when I walked across Glasgow Bridge into the Gorbals and passed the Great Synagogue. But as my loss moved to the background like a nagging toothache, I found myself sleeping better, and drinking and smoking less. I'd been given new responsibilities at the Gazette and even my relationship with Samantha Campbell seemed to have moved on to a surer footing. Sam was winning most of her cases at the bar, although it took her to Edinburgh every day and some nights. More, her chambers had hinted at some relaxation in their stance on married women taking silk. Perhaps I could make an honest woman of her before we were both too old for it to matter.

Capping it all, my erstwhile mentor and drinking pal Wullie McAllister had broken from his dwam, like Rip Van Winkle, and was now his former cantankerous self, albeit wheelchair-bound while his unused muscles – mental and physical – got working again. I heard that the ward sister in the Erskine convalescent home had come to his room wondering what all the noise was and found Wullie roaring and shouting and banging his bedpan. As though some Scottish Frankenstein had jolted a monster back into life. The day we got the phone call from Stewart, Sam and I leaped into her Riley and drove out to Erskine. We found him sitting up in bed behind a newspaper, fag in mouth, with a pile of discarded papers on the floor. After our squawking reunion had subsided he demanded to know everything that he'd missed.

'What was your last memory, Wullie?' I asked across his ash-stained blanket.

'Getting hit ower the heid by that bastard – sorry, hen – Charlie Maxwell. His goons grabbed me from behind and chloroformed me as I was coming oot the pub. See, if it had been a fair fight ...'

'You'd have slaughtered them, Wullie. I know. Sam and I found you in the stables at his castle. They gave you a good hiding. Do you remember that?'

He screwed up his face. 'Bits. Those sods – the twa sidekicks of Slattery?...