The root began to thicken, changing from a pale tendril to the solid, bark-skinned limb of a mature tree. She could feel, through the tree, the Dragon’s attempts to struggle, but the root held on with patient vegetable strength, and the huge creature couldn’t get any of its legs free to claw its way out.

For a moment, the contest hung in the balance, the Dragon struggling to draw breath, the dying tree tightening its grip, notch by remorseless notch, even as the rest of its body collapsed. Alice found herself holding her own breath, teeth clenched, fists closed so tight, her fingernails were four points of pain against her palms.

‘Well played, child,’ the Dragon said, voice unimpeded by the vine wrapped around its throat. ‘But we both know it’s not going to be enough.’

Alice held on for all she was worth.

‘Then,’ she growled, ‘I’ll think of something else.’

A deep, rumbling laugh echoed through her mind. ‘You still claim to have come here by accident?’

‘I told you,’ Alice said. ‘No one sent me.’

‘Fierce. Small, but fierce.’ A long moment passed. ‘Perhaps my sister has got more than she bargained for. In which case, there may be a chance . . .’

The Dragon’s voice echoed hollowly around the inside of Alice’s head.

‘Very well,’ it said. ‘I submit.’

No sooner had it said the words than the world began to dissolve around them. The sky went grey, then black, and the rocks underfoot fuzzed out into a grey mist and disappeared. It was like looking through a camera as it lost focus, but for sound and touch and smell as well as vision. For a moment, Alice felt like she was falling, alone in an infinite void. Then reality snapped into being all around her, and she was lying on her back on the dusty floor of the library, next to Isaac, one hand still gripping the cover of the ancient leather-bound book.

A last echo of the Dragon’s voice buzzed at the back of her mind.

‘And I will be interested, little sister, to see what you can do . . .’

She took a deep breath, inhaling half a pound of dust, and regretted it immediately. A coughing fit turned her on her side and doubled her over, raising more dust all around her. Some instinct made her keep hold of the book, which she clutched to her stomach like a drowning man grabbing a rope.

Alice could hear Isaac coughing as well, and as she brought her spasming lungs under control she realized he was hiccupping and laughing too, all at once. When Alice had regained sufficient breath to sit up, she found him lying on his back, the rent and torn remnants of his coat spread beneath him, with tears of laughter squeezing out onto his cheeks.