Ordinary life is endlessly fascinating, from the quiet hum of a communal meeting place to the clink of teacups in a village cafe or the ice cream van on a sleepy suburban street. These moments are so familiarly innocuous that we rarely stop to wonder what might lurk beneath them.

And that’s where the story begins.

As a crime and mystery writer, I find the most chilling tales don’t begin with bloodshed or bodies — they start with routine. With predictable lives, bordering on tedious, until something unravels. A misstep. A secret. A person who doesn’t quite belong. Or, in my book, The Girl In Flat Three, a smell that won’t go away. Suddenly, the cosy becomes claustrophobic. The familiar feels foreign. And the ordinary becomes the stage for something much darker.

This genre is sometimes called domestic noir, but isn’t it more appropriately named as the sinister ordinary? A genre that encourages the reader to look closer — to examine the kind neighbour, the spotless home, the polite hotel guest. To question the noises coming from the flat above? These aren’t gothic castles or abandoned warehouses. They are places we inhabit. And that’s what makes them dangerous.

Real suspense begins not in the extraordinary but in the almost possible. In the idea that the person who checks your fire alarms might plant something more lethal. That the inoffensive man in the supermarket queue isn’t browsing so much as stalking. It’s that sliver of doubt, once introduced, that swiftly spreads its tentacles.

I read and write in that moment — identifying the split second when everything shifts. A once locked door left ajar, a misplaced object that shouldn’t be there. A silence that lasts a little too long.

We live in a world built on habits and expectations. Most days follow a script. But it’s in the unscripted where that stories take shape.

So pay attention next time you’re in a hotel or walking down a familiar street. Notice the shadows. Watch for the hesitation in someone’s smile. The sinister doesn’t always arrive with a mask and knife held aloft. Sometimes, it wears a name badge and offers to change your towels.

The Devil comes to Bylands – Book Three in The Denman & Tallis Cotswold Crime Series coming later this year.