We drive through the headstone-studded battlefields of France towards the sunny south, to the stunning region of the Dordogne with its lazy rivers, fairy-tale castles and golden fields of tobacco and maize, a burnished chequerboard gracing the banks of the River Vezere and the yawning coils of the River Dordogne.

Expectation is high and rising fast as the miles speed past along the Autoroute Of The Sun. Sunflowers wave beneath schooners of cloud in a sky of blue. At Sarlat-la-Caneda, a town so photogenic it hurts your eyes to stare, I pop into a pharmacy to buy sunglasses - stepping straight out again into a downpour.

It rains all day, and the day after that. Not just patchy showers, but incessant, malevolent, constant sheets of bruising wetness that rattle the roof and pound the shutters of the cottage my wife and I have rented to share with two friends.

Its location is perfect, snug among softly wooded hills of the Perigord Noir in the northern hinterland of Sarlat. The house is cosy, very private, very French. We stare at the rainy blur of window panes: so what's to be done? We eye the unused map and glumly drive along glistening miles of hissing roads, past puddled fields and dripping woods, sometimes stopping at village cafes for a coffee and a moan. Someone says the whole week's forecast resembles 50 shades of grey. No, not what you're thinking.

"Let's do the caves. At least it's dry there," says my wife, and our friends perk up. "Let's start with Lascaux." In any international league of iconic caves Lascaux is big. Some call it a treasure house, a temple; it is simply a gallery of prehistoric art. The whole Dordogne region is a cave-explorer's dream, home to more caves than you could shake a stone-age cudgel at. With nothing better to do, Cro-Magnon man - and woman too - turned a hand to interior decoration. Now thousands of tourists flock to see it.

I research the subject. At Grotte de Villars, outside the northern town of Brantome, there are paintings of bison and horses and, unusually, of a human. The caves at Le Thot are graced by paintings of bison, ibexes and stags.

Lascaux, as it happens, is just a dozen miles from our cottage. The caves with their fabulous paintings lie under the hillside above the river a mile north of town. But the facts are simple: they won't be open, and we won't see them - unlike the four boys who, in September 1940, while walking their dog, discovered an opening in the rocks, the result of a landslide. Inside, in near darkness, ghosting the walls they discovered the shapes of ancient beasts, a mysterious cavalcade of art.

So amazing was the discovery that Montignac, after the war, became besieged by a stream of tourists, there to ooh and aah at the images: bears and stags, ponies and bison, and - it seems apt - a stone age dog. It was the quality of the work, and the scale of the labyrinthine gallery of images, huge and tiny, in mineral colours, reds, yellows, greys, that made Lascaux an ancient wonder of modern times.

Popularity, however, had its cost. Within 20 years the place was closed to prevent decay from that oohing and aahing public. It took another 20 years for a reproduction - Lascaux II - to open nearby, a painstaking, fabulous piece of homage. The crowds still come. But limits are placed on visitor numbers. You should book a day in advance at the tiny bureau beside the tourist office in Montignac, especially for tours in English.

We strike lucky. Cancellations have left us a niche. Our guide speaks English like a star from TV show 'Allo 'Allo but I find it hard to share her awe as we stare aloft. These paintings, in truth, are 30 years old, the work of a highly gifted expert. They are modern art.

As we emerge, the sky miraculously brightens. We drive to Montignac, park near a cafe by the river, enjoying a meal and the colourful view of trees and window boxes glowing in afternoon light. One of the boys who discovered the paintings spent his summers nearby in his grandmother's house. The plaque that tells his story and marks the dwelling is unmistakably surrounded by a spattering of bullet holes; the calling card of the Nazis.

The following morning sunlight streams through our bedroom window like a wake-up call. A fanfare. We head for Sarlat. Puffs of high cloud race across the sky, lifting our eyes from the coloured awnings of the weekly open air market.

Sarlat grew rich in the 15th century, thanks to tax concessions granted by the French king. A golden architectural age was born. Today, the old town nestles in a cleft between two hills, and the buzzing market meanders busily through its architectural fairy tale, rising in levels above the restless stream of buyers seeking bargains.

Golden stone, exquisitely crafted by long-dead medieval masons, catches the sunlight, creating a stage-set of church towers, turrets, tipsy roofs and tilting chimneys along the vennels that rise like ribs from the hollow town.

As I take the new panoramic lift, well worth the €5 (credit cards only), I rise to an angel's-eye view of high balconies, gargoyles, spires impaling the skyline. It is a gleaming vista above the weaving Rue de la Liberte where stalls are piled up with truffles, cepes and foie gras, with cheeses, spicy charcuterie, rustic loaves, jars in pyramids holding cassoulet and confit amid the rising babble of French. If we could simply change the costumes of the punters, or magic the vendors' vans into carriages and horses, we might be looking at a scene many centuries old.

The Perigord peoples adore their food. It is a reason to be here. Delicious vegetarian options in most local restaurants are barely a footnote. Black pudding, gizzard, neck of turkey, kidneys and chitterlings, are savoured. We have come to eat - on a modest budget. Sarlat's top restaurants do not charge a fortune, but better value is had in the sprinkling of pretty villages, or in bistros along the backroads.

That night in the nondescript village of Coly we come on the rustic - perhaps bog standard - La Table De Jean. The €19 fixed-price menu offers two courses and plenty of choice, all of it lip-smacking, flavour-packed succulence. We devour the rack of lamb, the 14oz steaks, washed down with glasses of local red, a robust blend of cabernet sauvignon, merlot and malbec (our driver excepted, of course). And go home to dreams of sunshine.

Alas, the next day the veil of rain haunts the valley once more. Undeterred, we drive due west towards a brighter sky, criss-crossing the winding river Dordogne, heading for Bergerac and the wineries that enfold it. At Monbazillac, famous for honeyed, delicate whites, we buck the trend and after a tasting or two, buy a dozen spicy reds at a decent discount.

But weather is fickle. The next few days are a mini-heatwave. Playing catch-up, we take rustic picnics of meats and cheeses and sparkling wine to various beauty spots in the castle lands that sit above the river - at Domme, an old fortress town that in summer floods with tourists, and at Beynac and La Roque Gageac. There are chateaux wherever you look, looming starkly against the skyline. We visit the splendid gardens at Marqueyssac, where the topiary is the finest in all of France.

The Dordogne proves equal to our dreams of it. The fortress town of Monpazier, which withstood the 16th century Peasant Revolts and the Wars Of Religion, is cobbled and cloistered and offers great lunches in tucked-away bistros. The Chateau de Castelnaud, perched on a bluff, stares across the river, straight at its ancient enemy Beynac. Returning that night to Domme, we idle an hour away on the ramparts sipping wine at a cliffside table on the esplanade, planning our final day's distractions.

"I want to see cave art," I say. "The real thing." So next morning we drive to Gourdon's outskirts. The Salle des Peintures Prehistorique, part of the complex of Grottes de Cougnac, is much less slick than Lascaux II; it offers pictures of ibex and elephant, deer and goat, the odd human figure, and, most tellingly, of the handprints of the artists, an oddly moving, fading signature.

"Most poignant," says the guide. And as you stand there your imagination frees itself, and flies. You picture the people who stood here before you, reaching out, their painted fingertips daring to dream.

TRAVEL NOTES

Getting there

Flybe has return flights from Edinburgh to Bergerac from £59.98 one way including taxes. Visit www.flybe.com.

Where to stay

Maison de Fleurs de Cerisier sleeps eight and is available from £295 to £700 per week. Visit www.ownersdirect.co.uk/accommodation/p8102549

What to do

For tickets to the caves at Lascaux see www.tosemitour.com or buy a ticket at the office in Montignac. Tickets costs €9.70 (adult) and €6.10 (child).