I suppose every decent holiday story ought to begin with a small disaster, and mine starts somewhere on the A1 autostrada with a sat nav that decided Passignano sul Trasimeno was more of a theoretical concept than an actual place. Three hours out of Rome, I found myself down a gravel track between olive groves, convinced I was pioneering a new route, only to discover I'd been circling the same cypress tree for twenty minutes. A farmer in a Fiat Panda waved me down, not to help, but to laugh. Fair play to him. I was driving a hire car the colour of a boiled sweet with a boot full of melted biscotti.

When I finally stumbled upon the property, tucked above the town with its terrace tilting towards Lake Trasimeno, I felt less like a traveller and more like a trespasser who'd won the lottery. The key was under a terracotta pot, exactly as promised, though I'd spent ten minutes checking beneath three others just to be thorough. The door creaked open on a kitchen that smelled faintly of rosemary and old stone, and I stood there with my suitcase, wondering if it would be terribly British to make a cup of tea before investigating further.

I didn't, of course. I went wandering instead, and promptly got lost again within half a mile.

Passignano's medieval core doesn't yield its secrets willingly. I took a left where I ought to have gone right, following a cat through an archway that narrowed until my shoulders brushed both walls. This is how I found the well. Not the tourist one with the plaque, but a deeper, mossier specimen behind a chapel that doesn't appear on any map I later consulted. An elderly woman in an apron was drawing water with a bucket on a rope, methodical as clockwork. She didn't speak English, I don't speak Italian beyond restaurant necessities, but she filled my water bottle anyway and pointed uphill with what I can only describe as conspiratorial encouragement.

I went up. There was no path, not really, just terraces of olive trees stepping back from the water, their silver leaves catching the afternoon like fish scales. Somewhere above me, a dog barked with the half-hearted enthusiasm of something that had seen this all before. I kept climbing because the alternative was admitting I had no idea where I was, and I've always found pride excellent fuel for poor decisions.

The ruin appeared suddenly, as these things do. A farmhouse shell, roofless, with fig trees growing through what had been a kitchen. I sat on a fallen lintel and ate the last un-melted biscotti, watching the lake turn from turquoise to bronze as the sun descended. A heron crossed the water with the indifferent grace of something that never gets lost. I thought about my sat nav, my circling, my farmer in the Panda. I'd spent the day trying to arrive somewhere, and instead kept finding places I hadn't known to look for.

That evening, back in the property's garden with a bottle of local Grechetto, I watched the lights of the Isola Maggiore flicker on across the water. Tomorrow, I told myself, I would visit properly. Take the ferry. Do things correctly. But when morning came, I found another wrong turn instead, another unexpected chapel, another conversation conducted entirely in gestures and goodwill. The island could wait. I was too busy being gloriously, accidentally elsewhere.