It's crushingly hot, 40C, and the children look like little legionnaires in their pink-and-yellow caps with flaps to protect the backs of their necks. We are staying in one of a row of six blindingly white Moorish houses on the beach, with pillars supporting the flat roofs over the tiled verandas. There are six of us, Gill and Juan, their bilingual daughters Gabriela, 5, and Rebeca, 3, another friend and I. Gill and Juan, who live at Rocafort, a few kilometres from Valencia, have rented this house on the Playa Almarda for a couple of weeks. Three steps down from the veranda, and you are on burning sand glittering with mauve flowers, sea holly and white, empty snail shells so light that a breath blows them from your hand. A prickly pear, succulent and spiky, sprawls its fruit and orange- red tufts against a wall at the back, and palm trees catch the setting sun. The sea, shelving sharply from smooth oval pebbles of purple and agate, pulls to the left, so that anything it takes is cast up farther along the shore. At least, beach balls, flip-flops and plastic detritus are; my spectacles, falling when I bent to wash sand from my legs, seem lost for ever. Gabriela, a video buff and word-perfect on The Little Mermaid, thinks a mermaid has got them - so, somewhere on a rock off the Spanish Main, there is a person with a scaly tail in a pair of Varilux lenses.

Sunday lunch at the San Jose, a cool conservatory-like restaurant overlooking the sea at Canet de Berenguer along the coast. A cannonade of fireworks celebrates the first communion of many of the children in the huge family parties at the long tables. No doubt the placement is dictated by pecking orders and internecine feuds, but everybody is dressed up and relays of tall, conical bottles of red wine, like the flasks of bath essence you see at Heal's at Christmas, enhance the festivity. I've discovered a delicious, ruby-red drink myself, Bitter Kas, non-alcoholic, Campari without the camp. Sizzling paellas the size of small islands, bristling with crustaceans, rocky with shells, are dismantled, pyramids of tiny bivalves are demolished, white calamari slither from their rings of batter and dangle worm-like from forks. There are plenty of good things for vegetarians, too.

It's best to go out very early, or late in the evening, to see the natives of the playa at work. Dung beetles assemble in the wake of a dog and transform the mess into a large and perfect sand-ball, black ants have made a long road, a four-lane motorway, and pass each other ceaselessly on their business to and from their city in the cracked earth of the scrub. We have sat by candlelight on the veranda at midnight while the sound of cicadas comes from the curry plants that waft the vapours of a delicate cuisine all around while a tabby cat stalks the beach and moths hover.

Back in Rocafort, and Gill and Juan's garden, vivid with crimson and magenta bougainvillaea, is a delight of scent; honeysuckle and jasmine and pink-and-white-striped lilacs pour out their perfume into the night air cooled by the sound of running water as circular motors clean the pools in neighbouring gardens. We drive to Albufera, a vast, magical lake beyond paddy fields, with a few white horses against an ultramarine sky. A motor boat negotiates narrow channels through reeds and rushes 20ft tall, and herons and white egrets fly and roost, and fish leap. Bronzed or mahogany does not describe our guide, who has the air of knowing that, if he were in a story, he would be some local deity steering us towards a mythic transformation. Gill's mobile phone, booking a restaurant in Valencia, cannot break the spell, and then she asks the man to turn off the engine, and we drift.

Valencia, in its soft, faded stone, seems a city that is very much itself, unaffected by tourists. Light falls from the glass dome of the enormous Mercado Central, and red, yellow and blue reflections from stained glass strike stalls heaped with what looks like enough food to feed the world. There are jewellery and cosmetics, racks of workaday print-house frocks, anything your heart or household could desire. We drink thick glasses of the local speciality, horchata, made from earthnuts, and then I find the stall I want. Souvenirs. A woman wraps with great care, in tissuey brown paper, each doll-sized paella dish and figurine, the Valencian cockerel jug and the yellow-glazed, green-splashed jug for olive oil, and these old postcards showing men in Valencian dress serenading ladies on the guitar, and little boys in cardinal-crimson satin among the orange groves of the song that has been playing an accompaniment in my head since we arrived.

Shena Mackay's latest novel, The Orchard on Fire, is published by Heinemann, pounds 12.99.