‘You have an exceptional talent. You simply have to let the magic flow through you. You have to feel it – in here.’ He runs a hand over her belly and she flinches from his touch. He’s laid hands on her before, but that was to correct her posture. Not a caress.

Before she can say anything, he raises his sceptre and intones, ‘Papilionem ostenderem.’ The spell sounds like a song on his tongue, sublime in its simplicity. As the words leave his mouth, the butterflies at her feet rise up, fluttering all around them. Each is a vivid colour – blue, pink, green, white and orange, their fragile wings perfectly formed.

She laughs to see the creatures returned to life and he leans forward and whispers in her ear. ‘You have to let the energy rise inside you. You have to open yourself to its power; you have to give yourself to it completely.’

She nods, confused, her heart beating as fast as the butterflies’ wings.

‘I can help you … if you give yourself to me.’

He leans forward to kiss her but she turns her head away. The dancing butterflies vanish as quickly as the ageing wizard’s smile. His knuckles tighten around the sceptre, his gemstone rings flashing as hard as his eyes.

‘You look forward to my visits, do you not?’ he asks.

‘Of course, but –’

‘You’re eager to accept my teachings, and yet when it comes to giving me something in return …’

The girl bites her lip. When he met her by the lake weeks ago and offered to tutor her in magic, he didn’t mention wanting anything in return. Before she can decide on the proper response, he runs a finger down her cheek. ‘You truly are a beauty. Those eyes, as green and wild as a mermaid’s, and those lips … red lips made to be kissed.’

She wants to turn and run away, but shock keeps her rooted to the spot. This is all her fault. She had no idea he felt that way about her and now she’s going to offend him. Her words come out in a shameful rush.

‘I’m sorry. I didn’t realise you … I’d never have taken up your time if I’d known.’ She prepares to beg for his forgiveness, to apologise for embarrassing them both, but Merlin raises his sceptre, forcing her lips shut. Panic rises inside her. She feels helpless, a tiny insect under his command.

His breath is hot on her neck, the cloying, musky smell of his incense overpowering. ‘I know you feel the same way. You just have to open your heart to me, give yourself to me.’

Her gaze darts around the room. She wishes she could call for her sisters, but no one knows she’s here and her mouth is sealed up.

‘I can help you. You want that, don’t you?’ he murmurs.

She nods, desperate to be free from his control, and he releases his hold on her. Gasping for breath, she raises her arm and utters the first spell that enters her mind, casting a net of protection before her. The silver cage glitters in the air for a moment, and then Merlin raises his sceptre and it falls to the ground.