Polly sits at her teacher’s kitchen table and thinks about what lies ahead. She knows she is going to have to be braver than she has ever been. And cleverer than she has ever been. But frankly, she would rather be home in bed.

‘Does it have to be me?’ she asks her teacher. She didn’t mean for her voice to come out quite so grumpy, but her head is hurting and her hand is hurting and it has been a very long day. Escaping a fury of crazed witches and being bitten on the hand by a frightened monster aren’t exactly the things that make you want to take on the world when you’re only nine years old.

Polly rests her sore hand on the table and closes her eyes. The potion Miss Spinnaker has dabbed onto the bite has calmed the throbbing, and the swelling is beginning to disappear. When she opens her eyes again she sees her teacher looking at her kindly.

‘I’m afraid so, Polly,’ Miss Spinnaker says. ‘It’s true it’s a little surprising the stones have chosen someone quite as –’ she pauses as she considers her words carefully, ‘well, inexperienced as you, but we must trust them. They will tell you what to do. Don’t worry. I am here and I will help you as best I can.’

‘Me too!’ says Buster eagerly. He wipes ju-ju fruit juice from his chin with his big, hairy paw. ‘I am brave and strong and I would absolutely love to be part of an adventure.’

Polly sighs. Only a few days ago her life was so predictably ordinary. Normally, at this time of night, she would be snuggled up next to her mother watching TV, their pet bortal snoring on the rug and her older sister, Winifred, picking at her black nail polish in the beanbag in front of them. Instead, she is hiding out in her teacher’s little cottage with her best friend, while a nasty gaggle of witches is out there looking for them.

That’s what you get for trying to be a hero, she grumbles to herself, and for a moment Polly regrets having stood up for her oldest and dearest friend when he was being bullied in the gallery for showing his feelings. But when she looks at Buster, who is smiling at her goofily with a purple smear of ju-ju juice across his chin, she knows she never really had a choice. Friends stand up for friends, no matter what. There’s no two ways about it.

‘All right,’ she says, taking a big, deep breath to fill her tummy with courage. She picks the stones up off the table and tucks them back into her pocket. ‘So, what’s our plan?’

Buster whoops with excitement.

Miss Spinnaker smiles. ‘Well, first of all, I think we should let your parents know you are safe.’ She stands up, gently easing her sleek black cat off her lap. It skulks into the corner, looking annoyed at being woken from its slumber. ‘They must be worried sick by now. I suggest we do a quick spin past on the broomstick to check in with them and maybe pick up some pyjamas and your toothbrushes. You can stay here tonight, if you’re allowed, until we figure out what to do next.’

A sleepover!  Polly’s heart soars. And another broomstick ride!  The fizzy excitement of their last ride, when Miss Spinnaker rescued them from the clock tower, still buzzes through her. Now their adventure is beginning to seem more appealing.

But when Polly looks across at Buster, she sees her friend has turned a paler shade of green.

‘Oh,’ Buster says, his mouth curling into a worried little grimace. ‘I guess it’s not a real and proper adventure if we just walk there, right?’

Polly laughs. ‘What happened to big, brave Buster, not scared of anything?’

‘I’m not scared of anything,’ Buster frowns. ‘I just get a little airsick, that’s all.’

‘I’ll fly gently,’ Miss Spinnaker assures them, and she bustles about, sweeping things into a midnight blue velvet bag she has slung over her shoulder.

Polly watches her teacher stride over to a tall glass cabinet where a collection of various witch things are on display. Miss Spinnaker stands in front of it, hesitating for a moment, before unclipping a long brass wand from its hook and tucking it into her bag.

Polly’s stomach tightens. ‘You’re bringing a wand?’ she whispers, glancing about as though someone might hear her.

Miss Spinnaker turns to face Polly, and her eyes glitter. ‘Polly, this is not a game,’ she says in a low voice.

Polly reaches for Buster’s paw. She feels it shrink a little in her own as the seriousness of their adventure washes over them.

Buster clears his throat. ‘I’m not scared,’ he says, his voice cracking. ‘No, not me. Not one bit!’

‘Me neither,’ says Polly loudly, mainly to reassure Buster. She knows that until everything in their town is back to normal, it is up to her to keep him safe.

‘It’s OK to be scared,’ Miss Spinnaker says. ‘To be afraid of something and do it anyway is the mark of true courage. And that is something you both have in cauldron-loads. All right, my lovelies, let’s go!’

She swishes past them towards the front door, cape billowing and bracelets jangling.