Lou remained a bit twitchy at my casual theft of the boat but when no police came screaming out of the woods to clap her in chains – and when the trailing cameramen didn’t stop us – she seemed to relax a little. Well, she trailed her hands in the cool water and leaned back, so she couldn’t have been feeling too edgy.

A small log cabin had just come into view, with a little flag in the Enchantment colours perched on top of its roof, when there was an odd rustling from the bank on our left. I swung my head around, expecting to see another otter or perhaps a bird. Instead what appeared from the undergrowth was a sheep.

It trotted along to the edge of the river and began chewing nonchalantly at a clump of grass. But this wasn’t a farmer’s field and there were no other sheep in sight. I couldn’t prevent myself from stiffening in alarm.

I grabbed hold of the rudder and steered the boat in. It was probably nothing, it was probably just a damn sheep. All the same…

Lou sat up. ‘What is it?’

‘Scottish wildlife,’ I said, with far more cheeriness than I felt.

She glanced over, spotted the sheep and laughed. Then she immediately sobered up. ‘You’re not going to kill it, are you?’

My worry was overtaken by confusion. ‘What? No! Of course not!’

Lou exhaled. ‘Oh, good. I thought that you might, you know, want it for dinner. Or something.’

I had no illusions about where my supermarket meat came from but that didn’t mean that I wanted it in anything other than a neatly packaged polystyrene packet with cooking instructions included. I was most definitely not in the business of slaughter. Too messy, for one thing. Although given that my stomach chose that moment to grumble rather loudly in between Harriet’s snores, I probably appeared prepared to chomp on the poor animal.

Instructing Lou to stay where she was with the others, I jumped out of the boat and walked slowly towards the sheep. It paused from its grassy meal and looked up at me. Then it returned to eating.

I scratched my head. I’d managed to communicate with the otter. I certainly had no problem when it came to talking to Brutus either, even if he did flatly ignore everything I said. How difficult could a sheep be?

I flicked my index finger, ready to draw the rune, but that first movement made me realise that I wouldn’t be able to manage it. Exhaustion was seeping into my bones and, rather than being sharp and fluid, even the start of the rune felt sluggish. I muttered a curse under my breath and stared at the sheep instead. It just kept on chewing.

I was hardly an expert in the ways of sheep. As far as I could tell, it looked perfectly normal. And getting jumpy simply because it was roaming around the Highlands, where there were probably a million other sheep doing exactly the same thing, was ridiculous. Probably.