I purse my lips, feeling it would be a betrayal of my mum, but maybe I should go and see the boatman. I could confront him with my mother’s story about witches and ask him outright. He was happy enough to talk about the folklore of the island before; even if he hasn’t seen anything himself he can tell me what the other islanders believe.

Tom eyes me sympathetically. ‘Once we get to the mainland, I’ll help you find a doctor who’ll come out and visit her.’ When I don’t say anything, he adds quickly, ‘Or we can try and find someone else in your family, whatever you think is best.’

‘Thanks.’

The word comes out tight and ungrateful, and I soften it with a smile. I’m thankful that he cares enough to want to help me. At the same time, I have no intention of returning to the mainland. I’ve only just found my mum – I’m not about to leave her.

‘You’re still coming back with me, right?’

I nod and smile more convincingly this time.

‘I know that look.’

‘What look?’

‘The half-nod – the one where you nod and give a funny little half-smile, usually followed by you biting your lip. The one that tells me you’re lying.’

I stare at him then look away, careful not to show my feelings.

‘And if I’m not mistaken, you just gave me the ice glare. If we were at work, you’d walk away from me now – off to harass some poor visitor with facts about mandibles when all they want to do is look at pretty butterflies and forget their problems for half an hour.’

‘Do you even know what mandibles are?’

‘Teeth or those long spindly things on their heads. My point is that you’d rather do anything than have a real conversation with me.’

I cross my arms, unsure which appals me more: the fact he’s given my facial expressions names or that he knows so little about butterfly anatomy, despite doing the same job as me for nearly a year. ‘You mean antennae? Mandibles are jaws – caterpillars have them but butterflies do not.’

‘Whatever. I know you take yourself off to the storeroom whenever the guys at work are arranging a night out. I even know about your hiding place. I looked in the window once and saw you squeeze yourself between two cardboard boxes at the back.’