'No, Chris, it's spring now,' Annis pronounced from inside the six layers of clothing she was wearing under her painting sweater. I had counted each one with regret as she put them on that morning.

'You're delirious with cold. It's winter. Deepest winter.'

'Well, officially it's spring now.'

'Officially, it's bloody freezing. Two paces away from this stove you'd perish in this perishing cold within minutes.'

'How would you know? You haven't moved away from that stove all morning.'

'It's only because I've been feeding it so diligently that your brush hasn't frozen to your canvas yet.'

'We'll get warmer weather soon; can't be long now.'

My own easel was empty since I was between paintings. Also between investigation jobs and between cheques from Simon Paris Fine Art, which was the reason for me trying to keep the wood burner in the studio going with any object that would burn. I fed another chair leg into the stove. We'd run out of logs days ago and I'd been burning oil rags, old paintings and broken furniture. Also furniture I had freshly declared broken that morning. 'Warmer weather soon is what you said last week. We've had snow showers since then. Actually, I'd prefer snow to this muck.' What had looked like morning mist had turned out to be a stubborn fog. Mill House and its ramshackle outbuildings lay at the bottom of the valley and it was often visited by lingering mists and miasmas, as though the place wasn't damp enough with the mill race hugging the house. Our studio – or rather the leaky, draughty barn we used for painting in – sat at the top end of the meadow, no more than sixty yards from the house, yet right then you wouldn't have known it. I walked across to the grimy windows we had bodged into the side of the barn to give us that Rembrandtish gloom Annis and I preferred for painting. Outbuildings and yard were hidden in mist except for a vague loom of dark in the damp greyness. 'It's like trying to paint inside a bottle of milk,' I complained. 'Semi-skimmed.' She ignored me and got on with her work – a large, complex canvas she had started the day before. From where she drew the inspiration for her mysteriously glowing canvases she never revealed, and over the years I had asked often.

It was five years ago now that Annis, then still a student, had somehow managed to squirrel her way first into my studio, then into the rest of my life. She helped with the private eye business if I asked nicely. She was good at it too, but much preferred to spend her time in the studio. Apart from studio, house and occasionally work, we also shared a bed, though this arrangement wasn't one to be taken for granted, since there was also Tim. Of whom more later.

For a while I stood and watched Annis watch paint dry. You'd probably need to be a painter to appreciate this pastime. For a painter, an unfinished canvas will always hold more fascination than a completed one. In fact, a finished painting is a bit like a good meal you had last week – a pleasant memory but offering no sustenance. Yet each time I finish a painting I slip into this limbo, like a man who is hungry but can't decide what he feels like eating.

Annis pulled her bobble hat deeper over her strawberry curls. 'Honeysett, I can hear you thinking; it's most distracting. Why don't you go and make soup or something?'

I brightened up instantly. 'Soup! Good idea. What colour?'

'Oh, any. Something big and cheerful that'll take you a long time to do.'

'I'll give it a go.'

Big I could do; I wasn't so sure about cheerful. The winter seemed to drag on for ever this time, and this wasn't the cold, clear and crisp season of the north but the dark, damp and dreary winter of the west of England. Outside, the air was saturated with moisture that settled in my hair. The rush of the mill race was muffled with mist, the vegetation sketched damp streaks across my jeans and the smell of wood smoke, normally so cheerful, filled my head with wintry darkness. More than anything, it was the lack of light that had finally got to me as it spread grey melancholy like botrytis across my life with months of low cloud and lingering mists. I could just about make out where the sun was trying to burn down through this murk, but reckoned it would be hours yet.

The postman had at last found his way down here. The cheque from the gallery I was waiting for wasn't among the pile of mail he had left on the hall table. Apart from a vet bill, it was all junk; I chucked it into the fireplace where it could do some good.

Right, then: soup, she'd said. I checked the larder, vegetable basket and fridge. Something big, she'd said. Well, you couldn't get much bigger than minestrone. What made a soup minestrone? Haricot beans, smoked bacon, tomatoes and tiny pasta shells. For the rest, you use whatever is around.

I shoved my biggest cauldron on the stove, glugged in enough overpriced extra virgin to turn the bottom green and set to. In went garlic, chopped onion and bacon. I yanked open a couple of tins of chopped tomatoes and tipped them in. Easy-peasy, this. A good squirt of tomato purée, a couple of pints of stock from the fridge and the phone rings. Far, far away in the attic office.

The fact that I had hidden my office up there gives some indication of just how committed and organized I was about running a serious business as a private investigator. And how successful it was in financial terms. Aqua Investigations was really a Yellow Pages listing, an answerphone in the attic and a grumpy painter who had forgotten what on earth made him start this detective lark in the first place. Too many black-and-white movies at too tender an age, I suspect.

Normally, I'd have ignored the call, let it go to the answerphone, then checked it later, but, in the hope of thus keeping the rest of my furniture out of the fireplace, I took the stairs three steps at a time and snatched up the phone at the fifth ring. Unfortunately, by then I didn't really have enough breath left to answer it.

'Aqua ... Investigations,' I panted.

'Good morning. Is that Chris Honeysett?'

'It is,' I wheezed.

He sounded doubtful. 'OK ... Is everything all right there? Is this a bad time for you?'

'No, everything's fine. I've been running ... bit out of breath, that's all. How can I help?'

'Keeping fit – important in your line of work, I expect. Now, my name is John Morton, and we would like to hire you to deal with a little matter for us.'

The royal 'we'? 'And who might "we" be, if you don't mind telling me?'

Here Mr Morton mentioned the name of a large British supermarket. Very large. Even I shopped there. Of course, if I'd had any sense, I'd have hung up immediately and gone and buried my loyalty card in the garden. And then built a garage on top of it just to make sure.

Instead, my stomach rumbled thinking of all that food. Perhaps they could pay me in smoked salmon and quince jam ... 'Don't you have store detectives for that kind of thing?' I asked, already distracted.

'This is different, Mr Honeysett; it's not an in-store matter. You do come highly recommended.'

Oh, really? That kind of talk usually meant they'd asked another agency and been told they wouldn't touch it. When pressed, they then mentioned my name in a sentence that also contained expressions like 'exorbitant rates', 'mad enough' and 'last...