Serge fixed us with his Al Pacino stare, his bowl of black truffles filling the room with a gassy whiff. "Two years ago, an old woman was taken," he said. "They tied her up until she told them where her truffles were hidden." After experiencing the Vaucluse area of Provence for the last 24 hours, I didn't doubt him for a minute.
Accompanied by my friend and fellow truffle novice Charlie, we had reached Avignon in the late afternoon. We wandered through the town's Christmas market as the clear sky smudged with evening.
Twinkling festive lights circled symmetrical lines of wooden huts selling everything from local glass jewellery to donkey salami. We stocked up on stocking fillers before stretching our legs past the enormous Palais des Papes and up to the Jardin du Rocher des Doms for a breathtaking view over the half-bridge immortalised in the song "Sur le Pont d'Avignon". The sunset danced over the Rhône river as the olive trees scented the surprisingly warm winter air.
Twenty minutes' drive northeast, we pulled into Carpentras, a delightful, butter-coloured Provençal town and our first real stop on the truffle trail. Our destination was a handsome 18th-century French townhouse, Maison Trevier, a B&B with vast, finely finished rooms and a courtyard garden replete with every herb. Opening the studded oak front door, Gina welcomed us like long-lost sons and showed us to our room. "Refresh quickly please boys. Tonight, we cook together."
Gathered in her cavernous kitchen, we donned aprons to try our hand at age-old recipes that served as a whistle-stop tour of the culinary riches of this region: pumpkins, candied fruit, olive oil and the centrepiece of the season, the obligatory black truffle. I busied myself mastering a pompe à l'huile, a sweet, orange-scented cake or bread that forms part of Provence's traditional 13 desserts, served on Christmas Eve to represent the 12 apostles and Christ.
"Regarde ..." Gina suddenly commanded, retrieving something from the fridge, "... la truffe". Being early in the season (January is the peak month), it looked humble enough, yet she rinsed it as carefully as if she was bathing the infant messiah. Slices were added to a bowl of eggs before scrambling and serving over wilted chard. It tasted holy. Feasting on the fruits of our labours with bottles of local Côte du Rhône, we could have been at a Provençal table two centuries ago.
Morning broke in a bustle of noise and we followed it to the town's truffle market. Mustachioed men gathered around tables to barter on the price of these "black diamonds" selling for upwards of €300 per kilo. Serge, a local restaurateur and Michael Corleone lookalike, shook our hands. "You come to my place for lunch." It was an offer we couldn't refuse.
Chez Serge didn't disappoint. Fortified with his truffle-buttered bread and stories, we drove deeper into the Vaucluse area surrounding Mont Ventoux. The looming silhouette of this emblematic mountain, a favourite among walkers, dominated the horizon to the east. Vineyards trimmed after the harvests rolled across the undulating countryside, interspersed with corridors of lavender and stands of white and green oak trees, the truffle's host.
At the fine farmhouse B&B Les Ursulines, close to Valréas, our faltering French greeting to owner Jean-Pierre was met with an enthusiastic response that somehow led to us being bundled into his car and tearing up a dusty road to meet Jacques and Diane, a weary-looking truffle hound on a length of rope. Both eyed us suspiciously.
Jean-Pierre reassured us, "People get nervous on truffle hunts. Dogs get stolen."
We knew the feeling. Handshakes were exchanged and we were off again to a fenced-off field of oaks. After 10 minutes, Diane was proving her worth. We dug up the truffles she detected and were rewarded when our hosts insisted we pocket a specimen as payment.
We celebrated in style, sampling wine at Coteaux de Visan near Valréas, before a supper of scallops and wild boar at Le Coquelicot restaurant. The pervading truffle smell hung around us, and fellow diners slapped us on the back, raising their glasses knowingly. We felt acclimatised.
The beauty of Richerenches was arresting in the morning sun. This ancient Knights Templar enclave, 10 minutes' drive from Les Ursulines was a reminder of the historic affluence of this area. Medieval defensive walls encircle a road-free village of picturesque streets that plays host to a fervour-filled truffle mass in January. The 3,000-strong congregation even swaps the usual wafer for a slice of the stuff.
At the Saturday market, locals showcased homemade rillettes of boar and rabbit alongside wines and apricot nougat. From the back of hatchbacks, truffle pickers sold their wares in clandestine fashion, hiding their financial transactions from view. The comparisons with drug dealing went beyond the dizzying head rush at the overpowering scent. "The truffle is part of the black economy," Jean-Pierre explained. "No tax".
Appetite duly stimulated, we headed south into the Gard, dropping in for lunch among the faded grand façades of the canal-side town of Beaucaire. The front-room feel of restaurant L'épicerie de Cécile was worth the detour. Cécile doesn't believe in menus and serves whatever she wants from her trip to the morning market. It's a philosophy that works; local specialities of roast apple with goat's cheese and brandade de morue – an emulsion of salt cod and olive oil – were fantastic, washed down with the local rosé, Châteaux Mourgues du Grès.
Our final stop was Nîmes, a city with more layers than a mille-feuille. All thoughts of stretching out at our hotel, Le Cheval Blanc, were abandoned when we opened the shutters to the awesome sight of France's oldest Roman amphitheatre directly opposite. Lunch was climbed off around its ancient tiers, learning about the gladiatorial combat that happened beneath, before a stroll through Nîmes' smooth stoned centre to find the Roman temple of Diane and the vast turquoise spring that gave the city its name.
As night fell, the streets came alive with Christmas lights, festive music and shoppers. We rested on the steps of the Maison Carrée, the illuminated columns of this Roman temple reflected in the glass of the Norman Foster-designed Carré d'Art gallery across the square. We reflected too, on the joy of finding treasure both freshly buried in the Provence soil and ancient, in the heart of a city.
Travel essentials: Provence
* Tickets are on sale for Eurostar's London St Pancras-Avignon Centre service (08432 186 186; eurostar.com) – but frustratingly for truffle hunters, it operates only on summer Saturdays from 7 July to 1 September (inbound, 14 July to 8 September). On other days you must connect in Lille or Paris. Fares start at £119 return, through Rail Europe (0844 848 4070; raileurope.co.uk).
* Maison Trevier, Carpentras (00 33 4 90 51 99 98; maisontrevier.com). B&B from €125.
* Les Ursulines, Domaine la Grand Grange, Valreas (00 33 4 90 35 02 96; chambredhote84.com). B&B from €58.
* Le Cheval Blanc, Nîmes (00 33 4 66 76 05 22; lechevalblanc-nimes.com). Doubles from €115.