Buster tosses Polly up onto his shoulders and the two of them bound off deep into the forest, before Flora and Mortimer can notice they have gone. Polly knows Mortimer is kind and that he probably didn’t mean any of those things he said, but he and Flora never asked to be pulled into this terrible mess.

Polly can’t wait around for Miss Spinnaker any longer. She knows where she is meant to be, even if her teacher has forbidden her from going there. She doesn’t have a choice. She is a Silver Witch and the stones have told her that this is what she must do. Somehow, she knows there is something in the Hollow Valley Mines that will make things right again. Something to do with her father.

Polly hasn’t told Buster about the vision the stones sent her yet. She has been waiting for the right time. For now, all she can think of is to get away from Mrs Halloway – and fast! For all they know, she may still be flying overhead, scanning the trees, desperate to hunt them down.

Buster runs as fast as he can until they reach the deepest, darkest part of the forest. Here the light is dim and the trees are so closely packed together that even the birds no longer swoop through. This is where they will hide for now.

Buster slips Polly off his shoulders and onto the ground. He puts his paws on his knees and leans against a tree trunk to slide down into a squat. ‘Do … you … have … any … water?’ he pants. His fur is covered in a sheen of sweat.

‘Oh!’ Polly says. Her brow furrows. She slips the velvet bag off her shoulder and rummages about in it, even though she knows this is the one vital thing she forgot. ‘I have pricklefruits?’ she says, holding out some of the pink, spiky fruit.

Buster takes one of them and peels back the coarse skin with his teeth. He sucks at the juice, but Polly knows it won’t be enough to keep them going for long. She burrows into the bag a little deeper. ‘And, look! I have Miss Spinnaker’s wand. And her old spell book, too!’ she says, her voice full of hope. ‘Maybe there is a spell in here to find water?’

She sits on the dirt beside Buster and opens the old exercise book across her knees to read out the list of spells on the front page. As usual, when she tries to read the words, the letters dance across the page. She traces her finger along one line as if to hold it steady, and slowly reads out the words. ‘Rock mo … ving smell …’ she begins.

Buster snorts with laughter, spraying pricklefruit everywhere. ‘Rock moving smell!’ he hoots. ‘Ha! That’s hilarious! Good one, Polly!’

Polly frowns, snapping the book shut. ‘It’s not funny, Buster!’ she says, shoving it onto Buster’s lap. ‘You read it then if you’re so clever!’

Buster’s face falls. He stares at Polly, who looks away from him, her face scrunched up with hurt. ‘You can’t read?’ he says, astonished. ‘But you’re so smart!’

Polly realises this is the first time Buster has seen her try to read something aloud. He has no idea how difficult it is for her. ‘It’s got nothing to do with being smart or not, Buster,’ she grumbles. ‘Miss Spinnaker says lots of smart people have trouble with reading.’ She crosses her arms tightly and kicks at a clod of grass with her heel.

‘Polly,’ says Buster. ‘I’m sorry! I didn’t know you couldn’t read.’

‘I can read!’ Polly says. Her mouth bunches up tightly as she feels a familiar sting at the corners of her eyes. ‘I know the words. It’s just the letters in the books. They trick me. It’s like they move around when I’m trying to read them so I read out different words to what’s there.’ Her voice comes out low and small. ‘That’s why I’m so bad at school.’

‘Does Miss Spinnaker know?’ Buster asks. He is feeling Polly’s sadness and frustration so strongly now he has shrunk to almost the same shape and size as her, and his fur is tinged with a helpless shade of blue.

Polly shrugs. ‘A little bit. I don’t know how much. I try and hide it most of the time. But it’s getting harder. The witches at school make fun of me when I have to read aloud. They call me Pumpkin-Head Polly.’

‘Well that’s pretty stupid!’ Buster snorts. ‘Why would they think calling someone a pumpkin is a bad thing? Pumpkins are delicious. They should at least call you something that doesn’t taste good. Like weevils. Or spickleseed. Spickleseeds are horrible. My mum puts them in bread sometimes. They get in your teeth. Oh, but that doesn’t sound the same, does it? Spickleseed Polly doesn’t really work.’ He scrunches up his face as he thinks about it.

Polly giggles. She can never tell if Buster rambles on like this just to make her laugh or if this is what he’s really thinking, but it doesn’t really matter. Either way, he is the sweetest, kindest friend a witch could ever have, and he always knows exactly how to make her feel better.

She puts her arms around his big neck and hugs him tightly until he is back to his normal shape and size again. Then she tucks Miss Spinnaker’s book back into the velvet bag and swings it over her shoulder.

‘Well, we’re not going to find water sitting around here, are we?’ she says, standing up and holding out her hand.

When she tugs at Buster’s paw, he jumps up into a standing position.

‘And she’s strong too!’ he yelps. ‘Is there nothing this witch can’t do?’

Polly laughs. ‘All right. Enough silliness, Buster. This is a very serious adventure we are on!’

Buster pulls a serious face and glowers past Polly into the forest behind her. ‘Anyone out there who makes fun of my Polly or calls her Pumpkin-Head or Weevil or Spickleseed or anything mean like that has to deal with me!’ he growls menacingly.

Then he tromps off ahead and Polly has to skip to keep up with him.