We woke up without rushing, like wise old dogs who know the world isn't going to disappear while you laze around a bit longer. After doggy and human breakfast, we went up to Dunhill Castle, which looks less like a castle and more like the skeleton of one that forgot to put on any flesh. Open ruins, free and without fences: what amounts to my medieval adventure park. They say it was built over seven hundred years ago by the Fitzgeralds, those nobles who apparently didn't know about modern builders or concrete. I sniffed every stone as if I were looking for the last Templar bone. From the top you can see the whole valley and I barked at the wind as if I were summoning my army of imaginary squirrels.

But the real treasure was down below: the Anne Valley Trail, a path that winds like a happy earthworm between the river and the trees. Four perfect paws for two-and-a-bit kilometres to Annestown beach. Smells of salt, distant cows, offended ducks and humans breathing deeply as if they had discovered their lungs for the first time. The sun accompanied us without scorching and I was marking territory like an abstract artist of pee.

When we reached the coast, I peered out like a pirate captain in search of gulls with a diva complex. Nothing but sea breeze, rocks and a picture-postcard silence. And then, back along the same path, as my paws already knew the way as if they were doing the teleportation trick.

Around three o'clock, Dad said the magic word: car. Three-quarters of an hour driving east to Passage East, where we discovered that there was a huge boat that eats cars, humans and dogs without seasoning: the ferry. Ten euros, less than ten minutes and not even time to get seasick from the fright. We crossed the Barrow River estuary without detours. I was ready to jump into the water like a lifeguard, but Dad reminded me that I don't have an approved float.

In Ballyhack we disembarked with the elegance of a diplomatic dog and went straight down to Hook Head. There stands the Hook Lighthouse, which is not just any tower with a light bulb: it is the oldest working lighthouse in the world. It has been guiding ships for over eight hundred years without retiring, since monks lit bonfires at the top to prevent sailors from ending up parked on the cliffs.

Dad Edu went to the four o'clock guided tour, the last one of the day, while I stayed guarding the campervan like a commander on a secret mission. The guide told how the lighthouse was built in the twelfth century by the monks of the Rinn Dubhán monastery, who kept a flame alive night after night. He talked about shipwrecks, pirates, clueless Vikings, renovations, new lamps and legends that smelled of salt, smoke and fear. In the group there were four Americans who laughed even when the guide breathed. Dad came out delighted, saying that he had learned more history there than in years of school.

The guide, who was very nice, told Dad that we could spend the night sleeping at the end of the car park where there was no prohibition sign as in the rest of the car park. But the wind there didn't blow: it slapped. So we began a rolling retreat.

The first good place we found was the car park of Tintern Abbey, an old acquaintance of our deep naps. We didn't stop to snore, but to eat. It was already half past six and Dad hadn't had lunch yet, although he had breakfast almost at noon. I provided faithful company and two begging looks in case something fell.

After filling the stomach tank we set off again on wheels. But Google Maps decided to make a tasteless joke and sent us on an absurd detour: forty kilometres instead of twenty. I suspect the app has shares in petrol stations.

After half past eight we arrived at a very cool car park next to the coast, with views that even a cat would admire in silence. When we arrived there were several cars and a motorhome, but one by one they all left, as if someone had announced a mandatory shower. Now the place is our nocturnal kingdom, just gentle wind, rocks, the smell of the sea and a field of stars to lie down on our backs.

Tonight I sleep as a coastal spy in case a late Viking, an ambitious crab or a gull looking for a fight appears. Dad dreams of lighthouses and ferries. I dream of the invisible sandwich I smelled in the castle in the morning.