She ran over and pulled back the covers to reveal her baby brother, curled onto one side, sucking his thumb as always. Cat sagged with relief. She had overreacted; he was fine. Maybe Granny’s stories were starting to get to her after all. She began to creep out of Mikey’s room so as not to wake him when her bare feet crunched against something pointy and sharp. She stifled a yelp of pain and hopped back to see what she had stepped on. It was one of the charms Granny had made. Her mam must have knocked it away from Mikey’s cot when she was putting him to bed.

She bent to pick it up, meaning to tuck it back where it belonged, when she heard a low, wheezy chuckle from behind her. Her entire body went cold. Slowly, she spun around and came face-to-face with Mikey, standing up in his cot and looking out at her with an expression of interest.

‘Sorry, Mikey,’ she said. ‘I didn’t mean to wake you. Go back to sleep, OK?’

The boy said nothing. He simply stared at her with eyes that glowed the colour of green summer leaves.

That’s strange, she thought. Mikey’s eyes are blue like mine. Her sleep-muddled mind finally caught up and Cat realised with a shock that it was still dark. She shouldn’t be able to see Mikey’s eye colour from halfway across the room.

This was not her brother.

‘Who … what are you?’ she asked, clutching the broken charm so tight in her fist she could feel the iron nail digging into the flesh of her palm.

Not-Mikey didn’t answer. He just stood at the edge of the cot with that same smirk on his face.

‘Can you understand me? What have you done with my brother?’

Still, silence.

There had to be a way to make him talk. Granny would know.

‘Listen here, whoever you are. You better answer me or I’ll–’

‘Or you’ll what?’ said not-Mikey with a voice as unnatural as his eyes. ‘What will you do to me, Caitriona?’

With that, any hope that it was all a figment of Cat’s overactive imagination shattered. With sudden clarity she realised that she was talking to a real-life fairy changeling. A changeling who had done something with her baby brother. She knew she should have been scared, but at that moment all she felt was anger.

She balled her hands into fists. ‘I’ll call my Granny and she’ll make you talk.’

Not-Mikey’s cruel eyes danced with delight. ‘Ah yes, that’d be Mary Donnelly wouldn’t it? A formidable woman by all accounts. Tell me, how is she keeping these days? Is she well?’

Cat narrowed her eyes in suspicion. ‘She’ll be here later so you can find out for yourself, although if I were you, I’d be long gone by then. You wouldn’t like to meet my Granny when she’s mad.’

Not-Mikey laughed. ‘It seems that spiritedness runs strong in the Donnelly women. I knew there was a reason he picked you.’