“Your father has a big project on the island,” Mum had told me. “Bird Rock is only habitable during the summer apparently, so the trip can’t be delayed and … well, it’ll be an adventure, won’t it? Staying in an actual lighthouse. I’m sure the island is very beautiful at this time of year. There’s all that wildlife, the rugged coasts and ocean sunsets. We thought it would be the perfect opportunity for Rosie to enjoy her photography and for you to do some stargazing away from all the light pollution.”

I hated it when my mum did this – made out that something was being arranged for our benefit when we both knew it was actually all about what was most convenient for Dad, but it seemed we had no choice in the matter. We were being shipped off to the Outer Hebrides for two weeks whether we liked it or not.

And as the day got closer, I dreaded leaving more and more. My friends all seemed to have tons of exciting plans arranged – shopping trips and music festivals, sleepovers and movie nights, glamping and sunbathing. All stuff that I would have to miss out on.

To make it even worse, Dad’s new family would be 17there this time. His wife Kate was an ornithologist too, and they had a six-year-old son, our half-brother Charlie. I’d only met him once before, a couple of years ago at an awkward Rainforest Café lunch. He’d cried because they’d run out of mozzarella sticks and then spilled his drink everywhere. It had been both embarrassing and annoying.

When I’d googled the island, I’d found that Mum had been playing it down a bit when she described it as ‘small’. In fact, it was one of the most remote islands in the entire UK. We’d literally be the only people there. There weren’t even any shops or cafés. The only buildings were stone bothies that had been built by monks hundreds of years ago. And, of course, the lighthouse itself. Rosie was very excited about the lighthouse.

The morning we were due to leave, she came bounding into my bedroom where I was trying to panic-pack and threw herself down on my bed.

“Guess what?” she asked.

“Would it kill you to knock?” I sighed.

Boundaries and personal space seemed to be 18concepts that Rosie really didn’t understand, despite my best attempts to explain them to her.

“The lighthouse we’re staying in is haunted!” She beamed, as if she’d just told me we were staying in a hotel, and that it had five stars.