Bhutan -

policeman who looks no older than a schoolboy waves a bunch of nettles. "For respect," he smiles. "If someone comes barefoot, I sting their legs."

Fortunately, we all have shoes. Here in the mountains of central Bhutan, peasants in their festival best are flocking to the gilded roofs of Tongsa monastery. In the courtyard, hung with yellow banners, women with babies on their backs spread multicoloured mats among huge flasks of butter tea. I have no silk gown, no coral necklace or turquoise rings, but two little boys in shimmering blue invite me onto their mat. Masked dancers twirl on the flagstones, drums beat, cymbals clash, and all around ivory beads and garlands of skulls whip the air.

I knew Bhutan would be different. As we stepped off the plane on the tiny airstrip in Paro, two officers on duty greeted us with snowballs. On the edge of the runway, a snowman sprouted horns like a yak.

Paro is a sleepy little place; a fairytale village of willows and bamboo, snow-laden pines and toy houses mirrored in tumbling waters. Sculpted eaves and balconies run along the white walls and fertility signs in pastel shades promise good crops and healthy children.

Early in the morning I gaze up at the mysterious Taktsang. Legend has it that long ago a holy man on a flying tiger landed on this ledge, 2,500 feet above the valley. On the journey up through feathery pines, groups of children sell prayer beads and temple bells. Tall Buddhist flags flutter in the breeze. On the edge of the precipice, I look across at the small cluster of monastic buildings barely clinging to the cliff. Distant figures shuffle back and forth, cut off from the world. The valley spreads out beneath us, terraced fields and a ribbon of road winding to Paro and from there to Thimphu, the capital, 8,000 feet high and our next stop.

Thimphu turns out to be in joyful mood. Archers compete in a meadow, dancing around the pole whenever an arrow hits the target. Women cheer while children keep an eye on the cooking pots. Archery is the national sport and serious business.

It is worth wandering up the main street, lined with steps, and into dens full of sweets, chillies and rolls of prayer flags. Snowy peaks frame the temple and a policeman in white gloves directs the trickle of traffic with the grace of a ballet dancer. In the fortified dzong – seat of the government as well as a monastery – monks marvel at the pictures in our guidebook. Is that really their village? Is that someone they know perhaps? Meanwhile a novice with dark monsoon eyes blows up balloons under a rose bush.

Having admired the religious paintings and stamps in the Paro Museum, in Thimphu we explore the National Library and its rows of loose-leafed books lovingly wrapped in orange cloth. Down by the river, men chisel silver and gold and a family makes paper in the snow. A lonely weaver shelters by a wall, heaving across the loom attached to her waist to create the bright geometrical patterns typical of Bhutanese fabric. Almost everyone wears the hand-woven traditional dress, men in knee-length gowns with sweeping cuffs, women in long wraps fastened on their shoulders with silver clasps.

After Thimphu, the Dochula Pass at 10,000 feet feels cold and deserted. Snow clouds tumble across the sky and pines grow precariously on the icy slopes. Even the prayer flags seem frozen. I spot a rare takin, a golden flash through the trees, but the native black bears stay out of sight.

By nightfall, we have reached Punakha, in a tropical valley ablaze with bougainvillaea and poinsettia trees. Farmers herd their goats while cows stare at the roadside. The earth is bright red. We feast on rice with lentil sauce and I burn my tongue on chillies I mistake for green beans.

The trek starts the next day beyond a rickety footbridge. We plod across the muddy rice fields then head up, leaving the last truck and the dzong basking in sunshine at the confluence of the rivers. All is silent but for our footsteps and the bells of ponies laden with bags and camping gear. Panting through silvery pines, laurels and rhododendrons, I shed one layer of clothes after another.

"Where is your car? Why do you walk?" asked a man with an eight-year-old boy. It was hard to explain the joys of trekking; he had walked for days, sleeping in caves, to barter yak meat and juniper for rice. Yellow butterflies with blue spots on their wings flutter on the path. There are mauve primulas, wild roses, quinces and tall hedgerows of sage which leave their scent in my hair.

For two days we roam the hills, up and down passes, around shrines and waterfalls, through scrubland and forests and villages where children pop out of haystacks and splash by the fountains. They thank us for taking their picture and cover their mouth as they speak, in order not to pollute the air we breathe. In the evening we huddle around the kerosene lamp, listen to the horseman singing of love and pour a drop of brandy in our tea to keep out the cold.

The last camp is in the lush Sha valley, where mandarins hang like baubles on the trees. The prayer wheel tinkles all night by the rushing stream and I dream of mountains and paddies rolling across the land.

There are no paddies on the way to Tongsa. The road – a ledge threatened by rockfalls – snakes painstakingly into the clouds. Slush becomes ice and snow; lichen draping the trees like giant cobwebs. We frighten a couple of boars, although the yak we meet is too busy scratching his head with his front paw to take any notice of us. Pele La, the Black Pass, looms through storm clouds until we plunge east into the valley. Far below, patches of grass and golden rape shimmer in the light.

Things are cheerier on a sunny riverbank. The Buddha's eyes on a painted shrine smile in all directions and white-capped birds twitter in the bushes. We picnic on cold roast potatoes, eggs and mango juice.

After a day in the wilderness, Tongsa rises like a mirage, taunting us elusively from across the gorge with golden roofs and white houses dotted on the mountainside. The dzong glistens above the ravine at the meeting point of the valleys. In our traditional lodge on the hilltop, roses and marigolds bloom under the window. The air is all incense and pines. Long after dark, we dance with our hosts, Bhutanese style, with sweeping gestures and shuffling feet punctuated by little leaps. The night outside is full of stars.

Dawn comes quickly, turning the snow on the mountaintops pink. It is the last morning of the Tsechu festival and there is much chanting and bell ringing. I look at the trail vanishing through the trees. Up there, in the hidden land of the Thunder Dragon, blue poppies wait for the spring.